TIA
STANDARD
Data Transmission Systems and Equipment
- Serial Asynchronous Automatic Dialing
and Control for Character Mode DCE on
Wireless Data Services
TIA-678-A
xxx 2004
TELECOMMUNICATIONS INDUSTRY ASSOCIATION
FOREWORD
(This Foreword is not part of the Standard)
This Standard is based on the work of the Portable Computer and Communications Association, PCCA STD101, including the provisionally approved Annex F and Annex I. Annexes F and I are renumbered Annexes B
and C respectively. Most of 5.2/STD-101, which is redundant with TIA/EIA-602-A or ITU-T V.250, has been
removed.
This Standard includes a new Annex D which defines PAD Control commands for Wireless DCE used in
Packet Data Networks. The commands were added as Annex D in the Table of Contents, and are defined in
the body of the Annex, which has been added to this revision. Appendix I has been modified to include
summaries of the commands, and the Scope has been modified.
This revision of the Standard incorporates changes detailed in TIA/EIA-678-1 Addendum 1 to TIA/EIA-678. In
addition, the references to ITU-T V.25ter have been replaced with references to ITU-T V.250. References to
other standards have also been updated or replaced with the applicable reference.
TIA-678-A
Data Transmission Systems and Equipment Serial Asynchronous Automatic Dialing and Control for Character Mode DCE on Wireless
Data Services
Contents
1. SCOPE ................................................................................................................................................................... 1
2. NORMATIVE REFERENCES ................................................................................................................................ 2
3. INFORMATIVE DEFINITIONS ............................................................................................................................... 3
3.1. INTENDED AUDIENCE ......................................................................................................................................... 3
3.2. STYLE CONVENTIONS......................................................................................................................................... 3
3.3. INTRODUCTORY DEFINITIONS.............................................................................................................................. 3
3.4. REFERENCE MODEL........................................................................................................................................... 5
3.5. PROTOCOL DEFINITIONS .................................................................................................................................... 6
3.5.1. End-to-End Protocol................................................................................................................................. 6
3.5.2. Command State Protocol ......................................................................................................................... 9
3.5.3. Additional Information ............................................................................................................................ 10
3.6. DCE FUNCTIONAL BLOCK DIAGRAM ................................................................................................................. 10
3.7. DCE OPERATING STATES ................................................................................................................................ 13
3.8. ADDITIONAL DEFINITIONS ................................................................................................................................. 14
4. DTE-DCE LINK (NORMATIVE) ........................................................................................................................... 15
4.1. Low-Level Logical DTE-DCE Interface ..................................................................................................... 15
4.2. Physical DTE-DCE Interface .................................................................................................................... 16
5. COMMAND STATE OPERATION (NORMATIVE) .............................................................................................. 17
5.1. COMMAND STRUCTURE .................................................................................................................................... 17
5.2. FUNCTIONS ..................................................................................................................................................... 19
5.2.1. TIA/EIA-602-A Action Commands ......................................................................................................... 19
5.2.2. ACE/DTE Interface Parameters ............................................................................................................. 25
5.2.3. ACE Parameters .................................................................................................................................... 25
5.2.4. Wireless DCE Extended Commands and Parameters ......................................................................... 26
5.3. RESULT CODES ............................................................................................................................................... 32
5.4. PARAMETER AND COMMAND SCOPE RULES ...................................................................................................... 35
5.4.1. Scope, Visibility, and Volatility Restrictions ........................................................................................... 35
5.4.2. Parameter Value Conflict Procedures ................................................................................................... 35
6. DATA STATE OPERATION (NORMATIVE) ....................................................................................................... 38
6.1. +WS45 AND +WS46 IN ON-LINE DATA STATE .................................................................................................. 38
6.2. REQUIREMENTS FOR CHARACTER STREAM OPERATION ..................................................................................... 39
6.3. TRANSPARENT CHARACTER STREAM ................................................................................................................ 39
6.4. RELIABLE TRANSPARENT CHARACTER STREAM ................................................................................................. 40
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ANNEX A: BUILDING ON THIS STANDARD ......................................................................................................... 41
A.1. EXTENSIBILITY FRAMEWORK ............................................................................................................................ 41
A.2. COMMAND SET EXTENSIONS ............................................................................................................................ 43
A.2.1. Commands in Proposed Annexes ......................................................................................................... 43
A.2.2. Manufacturer-Specific Commands ........................................................................................................ 43
A.3. RECOMMENDED ANNEX CONTENTS .................................................................................................................. 44
ANNEX B, MISCELLANEOUS COMMANDS ......................................................................................................... 45
B.1 SCOPE .............................................................................................................................................................. 45
B.2 NOTES ON INTERRELATED COMMANDS ............................................................................................................. 45
B.3 MISCELLANEOUS COMMANDS .......................................................................................................................... 45
B.3.1 Miscellaneous Parameter Commands .................................................................................................. 45
B.3.2 Miscellaneous Action Commands ......................................................................................................... 48
B.4 ADDITIONS TO +W COMMAND .......................................................................................................................... 51
ANNEX C - COMMAND EXTENSIONS FOR ANALOG CELLULAR DATA MODEMS ........................................ 52
C.1 SCOPE............................................................................................................................................................. 52
C.2 INVOCATION ..................................................................................................................................................... 52
C.3 CONFIGURATION .............................................................................................................................................. 52
C.4 ANALOG CELLULAR RESULT CODES .................................................................................................................. 53
C.5 ANALOG CELLULAR DATA MODE COMMANDS..................................................................................................... 53
C.5.1 Data over Analog Cellular Commands Query ...................................................................................... 53
C.5.2 Call Session Time Limit ........................................................................................................................ 54
C.5.3 Enable Cellular Result Codes .............................................................................................................. 54
C.5.4 Roam Lockout ...................................................................................................................................... 55
C.5.5 Phone Specification .............................................................................................................................. 56
C.5.6 Bias Modem Audio Gain....................................................................................................................... 56
C.5.7 Keypad Emulation ................................................................................................................................ 57
C.5.8 Phone Number Directory Selection ...................................................................................................... 60
C.5.9 Phone Battery Query ............................................................................................................................ 60
ANNEX D - COMMAND EXTENSIONS FOR PAD CONTROL IN PACKET NETWORKS .................................... 62
D.1 SCOPE............................................................................................................................................................. 62
D.2. PAD CONTROL PARAMETER COMMANDS ........................................................................................................ 62
D.2.1. Time-Independent Escape Sequence Enable ..................................................................................... 62
D.2.2. Disconnect Procedure .......................................................................................................................... 62
D.2.3. Local Online Echo Enable .................................................................................................................... 63
D.2.4. Forwarding Character Feature Mask ................................................................................................... 64
D.2.5. PAD Primary Forwarding Character ..................................................................................................... 64
D.2.6. PAD Secondary Forwarding Character ................................................................................................ 65
D.2.7. Packet Termination Upon Entering Online Command State................................................................ 65
D.2.8. No Data Disconnect ............................................................................................................................. 66
D.2.9. Data Disconnect ................................................................................................................................... 66
D.2.10. PAD Break Handling .......................................................................................................................... 67
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D.2.11. PAD Inter-Character Timer ................................................................................................................ 67
D.2.12. PAD Inter-Line Timer.......................................................................................................................... 68
D.2.13. PAD Input Buffer Editing Enable ........................................................................................................ 68
D.2.14. PAD Input Buffer Backspace Character ............................................................................................. 69
D.2.15. PAD Maximum Packet Length ........................................................................................................... 70
D.2.16. Display Memory Usage ...................................................................................................................... 70
D.2.17. Flush WAN-bound Data Buffer ........................................................................................................... 71
D.2.18. Display Supported Annex D Commands............................................................................................ 71
D.3. ADDITIONS TO +W COMMAND ......................................................................................................................... 72
APPENDIX I. COMMAND SET SUMMARY (INFORMATIVE) ................................................................................ 73
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1. SCOPE
This standard is applicable to the interconnection of data terminal equipment (DTE) and data circuit-terminating
equipment (DCE) employing serial binary data operation via the 100-series interchange circuits or data operation over
equivalent logical circuits.
This standard specifies extensions to the protocol elements, procedures, and behaviors described in ANSI/TIA/EIA-6021992 (TIA/EIA-602-A). These extensions are based on the “+” command prefix that is reserved by TIA/EIA-602-A for
standardized extensions, and adhere to the extended command syntax conventions established by ITU-T V.250.
This standard generalizes the protocol elements, procedures, and behaviors described in TIA/EIA-602-A, making them
applicable to DCE which operate over arbitrary data networks.
This standard defines the commands that the DTE may issue to:
(2)
Interrogate the capabilities of the DCE, including determination of what data network types and
associated network-specific AT command set extensions are supported by the DCE;
(3)
Select among supported data network types for subsequent DCE processing of automatic calling and
automatic call answering functions; and,
(4)
Select among supported DTE-DCE interface protocols.
This standard defines the responses the DCE shall issue to those commands. Where possible, these commands and
responses are taken from existing TIA standards.
This standard establishes required mappings between manufacturer-specific data network services and the DCE
protocol elements, procedures, and behaviors referenced in TIA/EIA-602-A (e.g. ring, dial, answer, busy, on-line data
state).
This standard establishes conventions for interworking of network-specific AT command sets in DCE which support
multiple data network types.
This standard establishes a minimal DCE Common AT Command Set consisting of:
(1)
Those commands defined in TIA/EIA-602-A and ITU-T V.250, and
(2)
Required extensions using the +W command prefix in accordance with ITU-T V.250.
This standard establishes conventions for uniform extension of its own scope and content through Annexes.
Annex D defines optional extensions to the protocol elements, procedures and behaviors defined in the original
standard, based on +WS and +WC command prefixes reserved for standardized extensions. The parameters in
Annex D only affect operation of the DCE in Transparent Character Stream mode and in Reliable Transparent
Character Stream mode, as selected by +WS45=0 or by +WS45=1.
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2. NORMATIVE REFERENCES
The following standards and other publications contain provisions or normative references which, through reference in
this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standards
are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility
of applying the most recent editions of the standards indicated below. Each publishing standards body maintains a
register of currently valid national, international, and industry standards published by them.
TIA-232-F-2000, Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing
Serial Binary Data Interchange.
TIA-561-2003, Simple 8 Position Non-Synchronous Interface Between Data Terminal Equipment and Data CircuitTerminating Equipment Employing Serial Binary Data Interchange.
TIA-574-2003, Simple 9 Position Non-Synchronous Interface Between Data Terminal Equipment and Data CircuitTerminating Equipment Employing Serial Binary Data Interchange.
TIA/EIA-578-B-2000, Asynchronous Facsimile DCE Control Standard, Service Class 1.
TIA/EIA-592-A-1998, Asynchronous Facsimile DCE Control Standard, Service Class 2.
TIA/EIA-602-A-2000, Data Transmission Systems and Equipment - Serial Asynchronous Automatic Dialing and Control.
TIA/IS-707-A-1998, Data Services Options for Wideband Spread Spectrum Systems.
TIA-136, TDMA Third Generation Wireless Standards
ITU-T V.24, Lists of Definitions for Interchange Circuits Between Data Terminal Equipment (DTE) and Data Circuit
Terminating Equipment (DCE)
ITU-TV.250-2003, Serial Asynchronous Automatic Dialing and Control
ITU-T V.253-1998, Control of voice-related functions in a DCE by an Asynchronous DTE
ITU-T V.80- 1996, In-band DCE control and synchronous data modes for asynchronous DTE
ITU-T T.31-1995, Asynchronous Facsimile DCE Control, Service Class 1
ITU-T T.32-1995, Asynchronous Facsimile DCE Control, Service Class 2
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3. INFORMATIVE DEFINITIONS
The following definitions apply for the purpose of interpreting this standard. In the event of conflicting definitions for the
same term in this standard and the Normative References, the definitions given in this standard apply (for purposes of
this standard only).
This standard groups informative definitions as follows:
-
Intended Audience
Style Conventions
Introductory Definitions
Reference Model
Protocol Definitions
DCE Functional Block Diagram
DCE Operating States
Additional Definitions
The subsection for each group may reference definitions in other subsections. For subsections which include a diagram,
the order of new definitions represents a functional traversal of the diagram. For the remaining subsections, new
definitions occur in alphabetical order.
All definitions, diagrams and statements in this section are informative, and are not meant to imply a preferred
implementation or to constrain implementation in any way.
3.1. Intended Audience
The audience for this standard includes: software interface designers for both DTE and DCE devices; applications
integrators; network implementation designers; and, end users requiring knowledge of the DTE-DCE interface.
3.2. Style Conventions
Throughout this standard, some words are highlighted to draw attention to them.
References to commands, parameter names, parameter values, and responses are printed in bold. For example: &F,
S3, 27, NO CARRIER.
Topical cross references and important new terms are printed in italics. For example: On-Line Data State.
References to titles of documents or document sections are underlined. In command and parameter descriptions,
default values are underlined. For example: Style Conventions; n = 0,1.
3.3. Introductory Definitions
Certain words and phrases, common in telecommunication standards documents such as this standard, occur only
rarely in everyday use. These words and phrases have precise and important meanings in this standard.
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Annex
An appendix of a standard, which provides additional information on a topic outside the
scope of the main body of the standard. Annexes may be normative, informative, or a
combination of normative and informative.
Informative
Material described as informative (e.g. an Informative Annex, a Best Practice) does not
express any requirement imposed by this standard, but provides the reader with
additional information which may be helpful in interpreting the standard or in implementing
compliant products.
Normative
Material described as normative (e.g. a Normative Annex, a mandatory default value)
expresses requirements imposed by this standard. To comply with this standard, a
product must satisfy all normative provisions. Normative material is often introduced by
the words “mandatory” or “required”.
Permissive
Material described as permissive (e.g. a permissive clause) is normative, and grants
permission for the DCE manufacturer to choose among several alternatives or within a
range of acceptable behavior while remaining compliant with this standard. Permissive
material is introduced by the words “need not”, “may” or “might”.
Example: “The DCE may implement an internal transport protocol.”
Provisional Standard
Term used to designate a standard which, although approved by the membership, may
be revised if the membership determines that compliance represents an unacceptable
hardship to manufacturers. Each new standard is considered a provisional standard for
six months after approval by the membership.
Recommendation
An informative statement or provision.
Reference
Another standard or document containing statements and provisions which are either
normative, or informative, with respect to this standard.
Reference Model
A system block diagram labeled to provide a basis for discussion of system components
and interfaces.
Requirement
A normative statement or provision.
Reservation
Material described as a reservation (e.g. reserved parameter values) is normative, and
prohibits the DCE manufacturer from implementing a described behavior until such
behavior is fully specified in an annex of this standard. A reservation is introduced by the
word “reserved”.
Example: “Parameter values 3 to 255 are reserved for future standardization.”
Restrictive
Material described as restrictive (e.g. a restrictive clause) is normative, and prohibits the
DCE manufacturer from choosing alternatives to a described behavior. Restrictive
material is introduced by the words “must” or “shall” .
Example: “The DCE shall respond to commands issued at either 1200 bit/s or 9600 bit/s”.
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3.4. Reference Model
Figure 1 diagrams the System Reference Model used in this standard to represent the DCE and associated system
components.
Id
DTE
Iw
Iw
DCE
Id
Remote
DCE
WDS
Remote
DTE
Ir
RES
Ii
Ii
RIS
WDS
Figure 1 - System Reference Model
The system reference model describes a generalized communication system. It leaves out many important system
aspects in order to emphasize common component-to-component relationships. A companion model, presented in
Section 3.5, Protocol Definitions, emphasizes end-to-end and peer-to-peer relationships.
In Figure 1, boxes represent system components. Lines connecting boxes represent the communication paths and
protocols used between system components. Vertical lines represent well-defined interfaces, the logical “junction
points” between system components.
This standard establishes mandatory behavior at the well-defined interface between the DTE and DCE system
components, designated Id in Figure 1. Well-defined interfaces such as Id allow manufacturers to build system
components given only knowledge of the associated interfaces and system component technologies.
Example: Manufacturer X may build the system component designated DCE in Figure 1, given only knowledge of the
interfaces designated Id and Iw. Manufacturer X need not understand, or even be aware of, the interfaces designated Ir
,Ii , or the system components designated RES and RIS. Similarly, Manufacturer Y may build the system component
designated DTE in Figure 1, given only knowledge of interface Id. The well-defined interfaces of the Reference Model
let Manufacturer Y’s product interoperate with Manufacturer X’s product.
For purposes of interpreting the System Reference Model of Figure 1, the following definitions apply:
DTE
Data Terminal Equipment. The network user’s computing device. Any terminal or
computer capable of providing commands and data to operate a DCE. In practice, a DTE
is a computer of any size.
DCE
Data Circuit-Terminating Equipment. The network user’s network access device. Any
device that connects a DTE to a communications network. This standard focuses on DCE
which interwork with network-independent DTE-based applications.
WDS
Wireless Data Service (or Wireline Data Service). The network accessed by the user,
through means provided by the DTE and DCE. Any communications network capable of
transferring data and state information between some or all of: DCE and Remote DCE;
DCE and RES; DCE and RIS.
Remote DCE
A DCE (as above) which establishes the far endpoint of communication. The end-to-end
peer entity of a DCE. Any device that connects a Remote DTE to a communications
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network. In practice, the Remote DCE is the network access device of some other
network subscriber engaged in communication with the user.
Remote DTE
A DTE (as above) which establishes the far endpoint of communication. The end-to-end
peer entity of the DTE. In practice, the Remote DTE is the computing device of some
other network subscriber engaged in communication with the user.
RES
Remote End System. A generalized system component which encompasses end-to-end
peer entities of the DCE and DTE. The combination of a connected Remote DCE and
Remote DTE may be considered a RES, but the designation RES does not imply
incorporation of either a Remote DCE or a Remote DTE.
RIS
Remote Intermediate System. A generalized system component which encompasses
intermediate (i.e. bridge, gateway, or router) elements of the end-to-end communication
path between DTE and RES. In practice, the RIS joins two WDS system components
when the RES is connected to the “far” WDS.
Remote Station
Any Remote End System, Remote Intermediate System, or Remote DCE.
Id
Device Interface. The DTE-DCE interface, which comprises shared physical (TIA-232-F)
and data link (asynchronous data, flow control) layers, and a modem control protocol (the
AT command set). This standard is normative for portions of the AT command set and
other protocols used at the Id interface.
Iw
Wireless Data Service Interface. The DCE-WDS interface, which is outside the scope of
this standard but which typically comprises at least shared physical and data link layers
and a network management protocol. This standard is in no way normative for the Iw
interface, which should be understood to represent any current or future network-specific
DCE-WDS interface.
Ir
Remote End System Interface. The WDS-RES interface, which is outside the scope of
this standard but which typically comprises at least shared physical and data link layers
and a network management protocol. This standard is in no way normative for the Ir
interface, which should be understood to represent any current or future network-specific
WDS-RES interface.
Ii
Intermediate Interface. The WDS-RIS interface, which is outside the scope of this
standard but which typically comprises at least shared physical and data link layers. This
standard is in no way normative for the Ii interface, which should be understood to
represent any current or future network-specific WDS-RIS interface.
NOTE: The System Reference Model may easily be applied to traditional telephone communication systems governed
by TIA-602-A. Consider: 1) the PSTN or GSTN to be an instance of WDS; 2) FAX/data modems to be instances of DCE
and Remote DCE; 3) a FAX machine to be an instance of RES; and 4) a dial-up X.25 or SLIP gateway to be an
instance of RIS. The System Reference Model applies similarly to other WDS types.
3.5. Protocol Definitions
3.5.1. End-to-End Protocol
Figure 2 diagrams the End-to-End Protocol Reference Model used in this standard to represent communication
between a DTE and a RES.
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RES
WDS
DCE
DTE
End-to-End Communication
Appl.
Appl.
Pres.
Pres.
Sess ion
Sess ion
Trans.
Trans.
Id
Network
I
Link
d
Physical
Serial or Bus
(other layers
as needed) (other layers
as needed;
network
Link
management
as needed)
Physical
Ir
Network
Iw
I
r
Link
Physical
Link
Unspecified
Physical
RF, Wire, etc.
Figure 2 - End-to-End Protocol Reference Model
The protocol reference model describes a generalized communication path between a DTE and a RES, which passes
through the DCE and WDS.
In Figure 2, boxes represent individual or multiple layers of the ISO 7-layer communications reference model. Boxes
containing triangles represent bi-directional translation of one protocol to another, and always span two underlying
boxes. Boxes having one or more common edges are elements of the same System Reference Model system
component.
Solid lines connecting boxes represent the physical connections between system components of the System Reference
Model (presented in Section 3.4, above). Faded lines with arrowheads represent peer-to-peer communication between
system components.
In some cases, the peer-to-peer communication shown in Figure 2 implements a specific interface of the System
Reference Model. Faded lines representing such communication bear the name of the associated interface (e.g. I d, Iw,
Ir).
Figure 2 represents the communications protocol stacks of four system components: the DTE, the DCE, the WDS, and
the RES. The stacks shown in Figure 2 for the DTE and RES each follow the familiar ISO 7-layer communications
reference model. The stacks shown in Figure 2 for the DCE and WDS are structurally mirror images of one another.
This section describes only the DCE stacks.
The following definitions apply for purposes of interpreting Figure 2:
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Appl.
The Application Layer (Layer 7) of the ISO 7-layer communications model. Regardless of
the actual underlying communication structure, end-to-end communication occurs
between Application Layer entities for purposes of discussion in this standard.
Pres.
The Presentation Layer (Layer 6) of the ISO 7-layer communications model.
Session
The Session Layer (Layer 5) of the ISO 7-layer communications model.
Trans.
The Transport Layer (Layer 4) of the ISO 7-layer communications model.
Network
The Network Layer (Layer 3) of the ISO 7-layer communications model.
Link
The Data Link Layer (Layer 2) of the ISO 7-layer communications model.
Physical
The Physical Layer (Layer 1) of the ISO 7-layer communications model.
Stack
A sequence of two or more contiguous layers of the ISO 7-layer communications model.
The height of a stack corresponds to the number of layers included.
DTE-Side Stack
The portion of the DCE shown in Figure 2 which executes the protocols of the I d
interface. Sometimes abbreviated to DSS in this standard.
WDS-Side Stack
The portion of the DCE shown in Figure 2 which executes the protocols of the I w
interface. Sometimes abbreviated to WSS in this standard.
Other Layers
Shown in the DCE and WDS sections of Figure 2. These layers may be absent or present
(network and manufacturer specific).
Network Management
Shown in the DCE and WDS sections of Figure 2. Network Management consists of
protocols executed between the DCE and WDS to control the operation of the network
(e.g. call setup and termination, power management, data buffering, flow control). These
protocols and associated layers may be absent or present (network and manufacturer
specific).
Note: Some manufacturers or networks may offer network-specific network management protocols at the Id interface for
execution by the DTE. These protocols are manufacturer and network specific, and are beyond the scope of this
standard. Notwithstanding, this standard requires that all DCE offer certain network-independent network management
protocols at the Id interface.
VReS, VRES
Virtual Remote System. A DTE-Side Stack which is indistinguishable from some Remote
Intermediate System or Remote End System at interface Id. The term VRES was used
extensively in earlier drafts of this standard; this section formalizes its definition for
purposes of continuity with earlier drafts.
WDS Type
The term WDS Type was used extensively in earlier drafts of this standard to refer to a
WDS-Side Stack; this section formalizes its definition for purposes of continuity with
earlier drafts.
Figure 2 illustrates how the DCE translates between the Id interface and the Iw interface. In addition, Figure 2 illustrates
four important concepts:
(1)
Portions of the Iw interface used for network management purposes may terminate in the DCE (i.e., the
DCE need not pass all network management primitives through to the DTE across interface I d);
(2)
The WDS-side protocol stack of the DCE must include at least physical and data link layers, but may
include higher layers to support “tunneling” or “reliable transport”;
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(3)
The heights of the DTE-side and WDS-side protocol stacks may differ, provided that the DCE can
provide the necessary protocol conversion to the DTE’s link layer; and,
(4)
Independent layer numbering and naming schemes may be applied to each peer-to-peer protocol stack
shown in Figure 2.
3.5.2. Command State Protocol
Figure 3 diagrams the Command State Protocol Reference Model used in this standard to represent the relationship
between the DTE and DCE during periods when the DTE is configuring the DCE rather than transmitting and receiving
data over its end-to-end communication path. This standard refers to these periods as Command State.
DTE
DCE
WDS
RES
Appl.
Appl.
Pres.
Pres.
Sess ion
Sess ion
Trans.
Trans.
Ir
Network
I
Link
d
AT Cmd.
Link
Physical
Physical
Serial or Bus
(other layers
as needed;
network
management
as needed)
Network
Iw
I
r
Link
Physical
Link
Unspecified
Physical
RF, Wire, etc.
Figure 3 - Command State Protocol Reference Model
Comparing Figure 3 with Figure 2 reveals three important differences. In Command State:
(1)
The DCE’s protocol translation block severs the connection between the DTE-Side and WDS-Side
stacks (except for certain network management functions described elsewhere in this standard);
(2)
The DCE makes the protocols associated with a new block labeled AT Cmd. available to the DTE via the
Id interface; and,
(3)
The DCE may continue to be engaged in communication with the WDS, even though the connection
between DTE-Side and WDS-Side stacks is nominally severed.
The following additional definition applies for purposes of interpreting Figure 3:
AT Cmd.
AT Command Set Interpreter. This protocol sub-layer receives “commands” from the DTE
and transmits “result codes” to the DTE, for purposes of configuring the DCE and
performing automatic dialing and answering functions.
Refer to Section 5 of this standard for a detailed description of Command State.
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3.5.3. Additional Information
NOTE:
The Protocol Reference Models shown in Figure 2 and Figure 3 may easily be applied to traditional telephone
communication systems governed by TIA/EIA-602-A. Consider: 1) the DTE-Side Stack to consist only of physical and
data link layers; 2) the Network Management to be the DCE’s ring detect, off-hook, and DTMF circuits; 3) the WDS-Side
Stack to consist of a data access arrangement and either simple modulation/demodulation, or a transport stack (LAPM,
MNP10); 4) the WDS to consist of the PSTN or GSTN; and 5) the RES to consist of a remote FAX machine or Remote
DCE / Remote DTE combination. The Protocol Reference Models apply similarly to other WDS types.
3.6. DCE Functional Block Diagram
Figure 4 shows relationships between functional blocks of a generic DCE configuration governed by this standard. The
reader is encouraged to compare with Section 3, Figure 1 of TIA/EIA-602-A.
Figure 4 - Functional Block Diagram of DCE
Boxes in Figure 4 represent DCE functional blocks. Horizontal and vertical lines with arrowheads represent typical
interfaces between functional blocks. Diagonal lines indicate either a parallel or “1-of-N” connection, as discussed below
for individual functional blocks.
NOTE: Figure 4 is a generalized version of TIA/EIA-602-A, Section 3, Figure 1, as follows: 1) TIA/EIA-602-A’s V.24
Interface is replaced by the more general DTE Interface Adapter block; 2) the RI signal shown in TIA/EIA-602-A is
understood to pass through the ACE, rather than directly to the V.24 Interface; 3) the Hook Control, Dialing Signals, Call
Progress Signals, and Ring Detect shown in TIA/EIA-602-A are understood to pass through the DCU, rather than
directly to the ACE; and 4) TIA/EIA-602-A’s GSTN Interface is replaced by the more general Network Interface Adapter
block(s).
The following definitions apply for purposes of interpreting Figure 4:
DTE Interface Adapter
The physical layer interface between the DTE and the DCE. This interface may convey
several parallel channels, or circuits, of information bi-directionally or uni-directionally
between the DTE and the DCE. A typical DTE Interface Adapter might provide a ITU-TS
V.24 physical interface for asynchronous serial data and parallel handshake circuits, as
described in Section 4 of TIA/EIA-602-A.
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ACE
Automatic Calling Equipment. The functional block within the DCE that accepts
commands from the DTE and issues responses to the DTE, to configure and control DCE
operation.
DCU
Data Communications Unit. The functional block within the DCE that translates data and
network management information bi-directionally between the I2 (DTE-side) and I3
(WDS-side) interfaces shown in Figure 4.
Network Interface Adapter(s)
One or more physical interfaces between the DCE and one or more WDSs. Network
Interface Adapters available on a particular DCE might include some or all of: a telephony
data access arrangement; an RF modulator and two-way radio; an infrared transducer;
other interfaces.
Shared State and Parameter Values
The set of parameters used by the ACE, DCU, DTE Interface Adapter, and Network
Interface Adapter(s) to configure and control operation of the DCE. Shared State and
Parameter Values may include WDS-specific data, non-volatile storage, internal
temporary storage, data buffers, and other types of storage, but must include volatile
read-write parameter storage.
Figure 4 identifies the Id and Iw interfaces described in Figure 1, as well as several representative internal DCE
interfaces.
I1
An internal DCE interface used figuratively in this standard to convey logical
representations of the states of physical interface circuits between the DTE Interface
Adapter and the ACE. Interface I1 includes logical circuits TD, RD, DTR, RLSD, RI, and
may include other logical circuits. The DCE may, but need not, include an I1 interface.
I2
An internal DCE interface used figuratively in this standard to convey data and network
management information between the ACE and the DCU. The DCE may, but need not,
include an I2 interface.
I3
A set of internal DCE interfaces used figuratively in this standard to convey logical
representations of the states of physical interface circuits between Network Interface
Adapters and the DCU. The DCE may, but need not, include an I3 interface.
This standard includes normative provisions which influence the internal operation of the ACE and DCU. The standard
specifies these provisions in terms of functional blocks considered (for purposes of illustration) to be internal to the ACE
or DCU.
Figure 5 shows the ACE in greater detail. The main feature of Figure 5 is the Command and Control Unit (CCU). The
CCU uses both the DCU and various AT Command Sets to process data.
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to
DTE Interface
Adapter
I2
Command and
Control Unit
(CCU)
I1
I4
to
DCU
I5
Common
AT
Command
Set
WDSSp ecific
AT
Command
Set(s)
ACE
Figure 5 - ACE Functional Block Diagram
Figure 6 shows the DCU in greater detail. The main feature of Figure 6 is the Protocol Conversion Unit (PCU). The PCU
performs protocol conversion between the ACE and one or more Wireless Data Services (WDSs), using a DTE-Side
Stack and one or more WDS-Side Stacks (refer to Figure 2 and Figure 3).
The DCE may include several DTE-Side Stacks, only one of which is used by the PCU at any time. The DCE may
include several WDS-Side Stacks, one or more of which is used by the PCU at any time.
to
ACE
I2
Protocol
Conversion Unit
(PCU)
I6
I7
DTESide
Stack(s)
WDSSide
Stack(s)
I3
to
Network Interface
Adapter(s)
DCU
Figure 6 - DCU Functional Block Diagram
The following additional definitions apply for purposes of interpreting Figures 5 and 6:
CCU
Command and Control Unit. The functional block within the ACE that accepts commands
from the DTE and issues responses to the DTE, to configure and control DCE operation.
Common AT Command Set
The set of commands recognized by the CCU in all DCE operating states which accept
and interpret commands.
WDS-Specific AT Command Set(s)
Zero or more sets of commands recognized by the CCU only while the DTE has enabled
specific WDS-Side Stacks for use by the PCU. While each command set typically
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TIA-678-A
contains unique commands, two or more WDS-Specific AT Command Sets may use
some or all of the same command names for equivalent purposes.
PCU
Protocol Conversion Unit. The functional block within the DCE that translates bidirectionally between the currently selected DTE-Side Stack and the currently enabled
WDS-Side Stack(s). The PCU defined in this standard is a superset of the DCE functional
block identified in Section 3, Figure 1, of TIA/EIA-602-A.
I4
A n internal DCE interface used figuratively in this standard to represent the means by
which the CCU parses and executes the configuration and control commands defined by
the Common AT Command Set functional block. The DCE may, but need not, include an
I4 interface.
I5
An internal DCE interface used figuratively in this standard to represent the means by
which the CCU selects, parses and executes the configuration and control commands
defined by selected WDS-Specific AT Command Set functional blocks. The DCE may,
but need not, include an I5 interface.
I6
An internal DCE interface used figuratively in this standard to represent the means by
which the CCU selects and executes the protocol defined by the selected DTE-Side Stack
functional block. The DCE may, but need not, include an I6 interface.
I7
An internal DCE interface used figuratively in this standard to represent the means by
which the CCU selects and executes the protocol(s) defined by the selected WDS-Side
Stack functional block(s). The DCE may, but need not, include an I7 interface.
3.7. DCE Operating States
The DCE operates in one of four states (refer to Section 5 and Section 6 of this standard for additional information):
Command State
In Command State, the DCE is not communicating with a remote station. The ACE is
ready to accept commands, and data received from the DTE on logical circuit TD is
treated as command lines and processed by the ACE. The ACE responses and
unsolicited result codes are sent to the DTE on logical circuit RD. The DCE signals
network alerts to the DTE on logical circuit RI. Typically, the DTE continuously asserts
logical circuit DTR. The DCE enters this state upon power-up, and when all calls are
disconnected.
Internal Processing State
In Internal Processing State, the DCE may or must ignore data transmitted by the DTE.
The DCE temporarily enters this state from Command State or On-Line Command State,
at the beginning and end of command execution.
NOTE: TIA/EIA-602-A does not identify the Internal Processing State as a separate DCE operating state, but describes
equivalent behavior in Section 5.3 and Section 5.4.1. TIA/EIA-602-A, Section 5.3 implies that the DCE may ignore data
for <100 ms at end of result code delivery. TIA/EIA-602-A, Section 5.4.1 specifies that the DCE must ignore data for
125 ms at start of command execution).
On-Line Command State
In On-Line Command State, the DCE is communicating with a remote station. The ACE is
ready to accept commands, and data received from the DTE on logical circuit TD is
treated as command lines and processed by the ACE. The ACE responses and
unsolicited result codes are sent to the DTE on logical circuit RD. Depending on the
implementation, data received via the selected WDS from the remote station during OnLine Command State may be either discarded, or retained in the DCE until On-Line Data
State is once again entered (by a command from the DTE). Data previously transmitted
by the DTE and buffered by the DCE may be transmitted from the buffer to the remote
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TIA-678-A
station via the selected WDS during On-Line Command State. Typically, the DCE holds
logical circuit RI inactive and the DTE continuously asserts logical circuit DTR. On-Line
Command State may be entered from On-Line Data State by a mechanism defined in
TIA/EIA-602-A or by other manufacturer-defined means.
On-Line Data State
In On-Line Data State, the DCE is communicating with a remote station. Data received
from the DTE on logical circuit TD is treated as data and forwarded to the DCU for
transmission via the selected WDS to the remote station. Data received via the selected
WDS from the remote station is transmitted to the DTE on logical circuit RD. The ACE
monitors data and control signals to detect events such as loss of the remote connection
and DTE requests for disconnection or switching to On-Line Command State. On-Line
Data State is entered by successful completion of a command to originate or answer a
call, by automatically answering a call, or by a DTE command to return to On-Line Data
State from On-Line Command State.
3.8. Additional Definitions
The following additional definitions apply for purposes of interpreting this standard:
Autobaud
The action of the DCE, when in Command State or On-Line Command State, of
automatically detecting the data rate used by the DTE to issue each command line. Once
the DCE establishes the data rate, the DCE will use this rate for all subsequent
transmissions to the DTE, including unsolicited result codes such as RING, until the DTE
changes the rate again.
Concurrent Multi-Function Operation
Selection and concurrent / interleaved use of two or more WDS-Side Stacks. Concurrent
multi-function operation is a topic of ongoing research and development, and is outside
the scope of this standard.
DCE Operating Mode
Any unique combination of Service Class, DTE-Side Stack, WDS-Side Stack, and
operating state (Command, On-Line Command, On-Line Data).
Direct Mode
Mode of On-Line Data State in which logical circuits TD and RD transfer data at the same
rate or rates in use on the DCE-to-WDS communications channels, and the DCE does
not buffer data in either direction or implement flow control. .This mode is defined in V.250
and referenced in the definition of the +IPR command. Refer to V.250 for additional
information.
Multi-Function DCE
A DCE which comprises two or more WDS-Side Stacks.
Multi-Modal DCE
A DCE which comprises two or more DTE-Side Stacks.
One-at-a-Time Multi-Function Operation
Selection and use of only one WDS-Side Stack at a time. This standard applies to one-ata-time multi-function operation.
Parameter Scope
The set of DCE operating modes in which the value of a parameter or state variable
controls DCE operation. Scope may be local (the value controls operation only in a single
or family of related DCE operating modes), or global (the value controls operation in all
DCE operating modes).
Parameter Visibility
The set of DCE operating modes in which the value of a parameter or state variable may
be examined and changed. Visibility may be restricted (the value may be examined and
changed only in a single or family of related DCE operating modes), or unrestricted (the
value may be examined and changed in any DCE operating mode).
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TIA-678-A
Parameter Volatility
The conditions under which the value of a parameter or state variable becomes invalid or
unknown. Volatility may be stable (the value never changes as a result of a change in
DCE operating mode), or unstable (the value may change as a result of a change in DCE
operating mode).
Ring Source Indication
The action of the DCE, when in Command State or On-Line Command State, of informing
the DTE of the WDS type associated with assertion of the RI logical circuit. Refer to
Section 4.1.1 of this standard for additional information.
Service Class
An internal DCE state variable or parameter which conditions the selected WDS-Side
Stack to transmit and receive voice, FAX, data, or other types of information. Selection of
a specific service class may limit the set of selectable DTE-Side Stacks. Under this
standard DCE may, but need not, provide selectable service class.
Single-Function DCE
A DCE which comprises only a single WDS-Side Stack.
4. DTE-DCE LINK (NORMATIVE)
4.1. Low-Level Logical DTE-DCE Interface
With reference to Figure 4, interface I1 comprises the low-level logical interface between DTE and DCE. The DCE must
drive and respond to logical circuits TD, RD, DTR, and RLSD at interface I1 (or equivalent), as described below. The
DCE may drive and respond to additional logical circuits; informative examples are provided below.
4.1.1. Mandatory Logical Circuits
DTR
Data Terminal Ready. Binary status transmitted from the DTE to the DCE. When
asserted, DTR indicates that the DTE is ready to control and respond to the DCE.
RD
Received Data. This logical circuit transmits octets, in-order and error-free, from the DCE
to the DTE Interface Adapter. Depending on its internal state, the DCE uses logical
circuit RD to transmit either information text and result codes, or data (data may include
packet-based communication primitives).
RLSD
Received Line Signal Detector. Binary status transmitted from the DCE to the DTE .
When asserted, RLSD indicates one of several conditions related to WDS network
management.
TD
Transmitted Data. This logical circuit transmits octets, in-order and error-free, from the
DTE Interface Adapter to the DCE. Depending on its internal state, the DCE interprets
octets received on logical circuit TD as either commands or data (data may include
packet-based communication primitives).
4.1.2. Optional Logical Circuits (Informative)
RI
Ring Indicator. Binary status transmitted from the DCE to the DTE. When asserted, RI
indicates a network alert to the DTE (typically, an unsolicited connection request).
CTS
Clear To Send. Binary status transmitted from the DCE to the DTE. When asserted,
CTS indicates that the DCE is prepared to receive data or other information from the DTE
across logical circuit TD.
DSR
Data Set Ready. Binary status transmitted from the DCE to the DTE. When asserted,
DSR typically indicates that the DCE is prepared to operate. The interpretation of DSR
may be manufacturer-specific.
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TIA-678-A
RFR
Ready For Receive. Binary status transmitted from the DTE to the DCE. When asserted,
RFR indicates that the DTE is prepared to receive data or other information from the DCE
across logical circuit RD.
RTS
Request To Send. Binary status transmitted from the DTE to the DCE. When asserted,
RTS indicates that the DTE is prepared to transmit data or other information to the DCE
across logical circuit TD.
This list is not meant to be exhaustive. Manufacturers are permitted to provide any combination, including empty
combinations, of these and other optional logical circuits.
Note: It is recommended that the manufacturer provide logical circuits DSR, CTS, and RFR. Provision of DTR,
RTS/RFR, and DSR aides compliance with emerging “plug and play” standards. Provision of RTS, CTS, and RFR,
along with a V.24 physical interface, permits support of hardware flow control which may be preferable to in-band flow
control for certain binary data applications. Neither of these DCE characteristics is required for compliance with this
standard.
4.2. Physical DTE-DCE Interface
With reference to Figure 4, interface Id comprises the physical interface between DTE and DCE.
The DCE must provide a physical interface at Id (or equivalent). The DCE may provide any physical interface capable of
conveying all mandatory low-level logical interface circuits between DTE and DCE.
DCE employing V.24 physical circuits 103 (TD) or 104 (RD) as part of the physical DTE-DCE interface, must comply
with the following provisions of TIA/EIA-602-A: Section 4.2 Character Formatting, and Section 4.3 Data Rates.
Note: Manufacturers are encouraged to comply with applicable telecommunications industry standards (e.g. ITU-T V.24,
TIA-232-F, TIA-561, TIA-574) when choosing a physical interface.
4.2.1. Physical Interface (Informative)
A manufacturer choosing to provide a V.24 physical interface at Id might implement the following circuits:
Circuit 102
V.24 physical circuit for signal ground.
Circuit 103
V.24 physical circuit for bit-serial, byte-asynchronous provision of logical circuit TD.
Circuit 104
V.24 physical circuit for bit-serial, byte-asynchronous provision of logical circuit RD.
Circuit 108/2
V.24 physical circuit for provision of logical circuit DTR.
Circuit 109
V.24 physical circuit for provision of logical circuit RLSD.
Circuit 125
V.24 physical circuit for provision of logical circuit RI.
The manufacturer might implement additional V.24 physical circuits and their associated logical circuits. Refer to ITU-TS
V.24, TIA-232-F, TIA-561 and TIA-574 for additional information.
4.2.2. Alternative Physical Interfaces (Informative)
4.2.2.1. In-Band Interface
A manufacturer might choose to implement the recommendations ITU-T V.80, which describes procedures for a DTE
and DCE to exchange control and status using only the data transfer path.
Under ITU-T V.80, logical circuits TD (103) and DTR (108/2) (and other DTE-to-DCE circuits) are multiplexed on one
physical circuit; logical circuits RD, RI and RLSD (and other DCE-to-DTE circuits) are multiplexed on another physical
circuit.
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TIA-678-A
If V.24 physical circuits are used to implement ITU-T V.80: circuit 103 could provide the DTE-to-DCE data path; circuit
104 could provide the DCE-to-DCE data path; circuit 102 could be used for signal ground.
4.2.2.2. Parallel and Memory Mapped Interfaces
This standard permits both serial and non-serial implementations of mandatory logical circuits. For example:
(1)
Manufacturer X might choose to provide a proprietary physical interface using a byte-wide bi-directional
I/O port, a data strobe, a direction flag, and an attention flag, multiplexing all mandatory logical circuits
through the I/O port. Such an interface would not be inconsistent with this standard.
(2)
Manufacturer Y might choose to provide a proprietary memory-mapped physical interface, with all
mandatory logical circuits implemented as dual-ported data buffers. The manufacturer might further
choose to use semaphores to prevent conflicting use of buffers, and interrupts to support high-speed
real-time communication. Such an interface would not be inconsistent with this standard.
This list is not meant to be exhaustive, or to imply a preferred implementation.
5. COMMAND STATE OPERATION (NORMATIVE)
This section applies to DCE operation in Command State and On-Line Command State, as defined in Section 3.7 of this
standard.
5.1. Command Structure
The DCE must support all mandatory commands defined in TIA/EIA-602-A, Section 6, as well as extended commands
defined in this standard. This standard defines modifications and extensions to some of the commands defined in
TIA/EIA-602-A, Section 6.
The DCE must conform to applicable provisions of TIA/EIA-602-A, Section 5 for all commands. The DCE must conform
to all applicable provisions of ITU-T V.250 for each extended command.
Note: This section, while normative, summarizes and elaborates upon material found in TIA/EIA-602-A and ITU-T
V.250. The reader is encouraged to review TIA/EIA-602-A and ITU-T V.250, to obtain a more complete understanding
of command structure.
The DCE must conform to the following additional provisions with respect to command structure:
(1)
The DCE shall support a command line of at least 80 characters, including embedded space characters.
(2)
Extended commands described in this standard and its annexes, which use the syntax described in ITUT V.250 and are unique to this standard must have names beginning with the +W characters.
(3)
Extended commands described in this standard and its annexes, which use the syntax described in ITUT V.250 and are unique to this standard must support testing via the =? suffix.
(4)
Any <string constant> used in extended commands described in this standard and its annexes shall be
bounded at the beginning and end by double quotes (ASCII 22 hex) whenever used or displayed by the
DCE.
Example: consider an imaginary parameter command +WCOLOR, which accepts a single text value
from the set {red, green, blue}. A compliant DCE would implement the following command syntax:
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TIA-678-A
Table 1 - Syntax of String Constants
Command from DTE
AT+WCOLOR=?
AT+WCOLOR=red
AT+WCOLOR=“red”
AT+WCOLOR?
Response from DCE
(“red”,”green”,”blue”)
OK
ERROR
OK
“red”
OK
Notes
Each allowed value in quotes.
The text value must be in
quotes.
Current value in quotes.
NOTE: The requirement to enclose each <string constant> in double quotes applies only to command parameters (both
input on the command line, and displayed as part of information text in response to "?" and "=?"), and not to information
text in general (e.g. responses to action commands such as +GMM need not be enclosed in quotes)
(5)
The exceptions to ITU-T V.250 syntax noted in ITU-T V.253 with respect to the +FCLASS command are
also granted in this standard. Refer to ITU-T V.253, Section 6.3.3.3.1 and Section 6.3.3.4.2.
(6)
The DCE is initialized to accept any type of command (whether it uses TIA/EIA-602-A or ITU-T V.250
command syntax) at the beginning of each command line.
(7)
This standard defines additional result codes, for CONNECT<TEXT>, see TIA/EIA-602-A,Table 1.The
DCE is required to implement the corresponding result code and numeric equivalent for each data rate
supported. The DCE is not required to implement any data rates other than those specified in TIA/EIA602-A.
(8)
The DCE shall accept commands which this standard or its annexes define as members of the Common
AT Command Set (i.e. commands defined at the I4 interface of Figure 5) in any operating mode, for any
supported WDS type.
(9)
The DCE may restrict acceptance of AT commands which this standard or its annexes define as
members of a WDS-Specific AT Command Set (i.e. commands defined at the I5 interface of Figure 5), to
only those modes and WDS types for which the commands apply.
(10)
The DCE shall maintain state information (except for the values of certain parameters, as described in
Section 5.4 of this standard) across changes in DCE operating mode.
For example, if the DCE is currently using a CDPD WDS type and the DTE commands the DCE to
switch to a GSTN WDS type, perform some operations there, and later switch again to the CDPD WDS
type, the DTE shall find none of the CDPD-specific parameters different from before, unless a DCE reset
event occurs.
(11)
This standard permits sharing of compatible S-register and extended parameter definitions among the
different modes and WDS types. S-register and extended parameter definitions intended for exclusive
use in a given mode or for a given WDS type should have a distinct manufacturer specific S-register
numbers or parameter names and definitions. These conditions apply for all WDS types and service
classes, unless an applicable standard explicitly states otherwise (e.g., facsimile Service Class 2).
(12)
The DCE shall return the ERROR result code to all DTE references to unsupported extended parameters
having names beginning with +W. The DCE may return a manufacturer specific result code to any DTE
reference to an unsupported manufacturer specific S-register or other extended parameter.
(13)
Any provided means of DTE-DCE and DCE-DTE flow control are not required to function in Command
State. If the DCE honors or requests flow control in Command State, it must do so for all WDS types and
service classes.
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TIA-678-A
Note: It is recommended that manufacturers provide the same flow control options and use the same flow control
settings in Command State, On-Line Command State, and On-Line Data State. Refer to Section 5.4 for additional
information.
(14)
In the event that the DCE has received no DTE command and is configured for automatic data rate
detection, the rate, word length, and parity used for result codes must be 1200-8-N-1.
(15)
When the DCE receives a command that changes the operation from autobauding to fixed rate, or from
one fixed rate to another, the change shall only occur after the complete DCE response. Word length
and parity shall remain the same as determined from autobauding or from other DCE capabilities.
(16)
When the DCE receives a command that changes the operation from fixed rate to autobauding, the DCE
shall resume the last rate, word length, and parity determined by autobauding before entering fixed-rate
operation. In the event that autobauding was not previously enabled, the results must be 1200-8-N-1.
(17)
When the DCE receives a command that changes service class, WDS type, or On-Line Data State DTEDCE protocol, the DCE shall maintain the current Command State DTE-DCE rate, word length, and
parity.
(18)
This standard uses decimal for all commands and result codes requiring numerical representations
unless otherwise noted.
5.2. Functions
The following descriptions of ACE functions and associated commands include information on both mandatory and
optional capabilities. All mandatory commands, parameters, and responses shall be implemented in devices claiming
conformance to this standard. If an optional capability is implemented in a DCE or ACE, the associated command(s),
parameter(s), and/or response(s) defined in this standard shall be implemented.
For simplicity, the following descriptions use a particular syntax; the actual syntax must vary in response to the values of
certain ACE parameters. For example:
(1)
Result codes are described in terms of their alphabetic format, except in situations where the setting of a
parameter directly affects the format (e.g., "V" and "Q" commands). The actual result code issued would
depend on the setting of parameters that affect result code formats.
(2)
The description of the OK result code for each command does not mention the fact that the result code
will be suppressed if any further commands appear on the same command line (see TIA/EIA-602-A,
Section 5.4).
Default values that are specified for some commands have been selected to provide proper operation of the ACE in its
initial state. Implementation of the specified defaults is desirable but not mandatory, with the exception of S3 (which has
a mandatory default value of 13). Default values for all parameters supported shall be specified by the manufacturer.
Each description may include standard subheadings, such as Syntax, Description, Abortability, Recommended Default
Value, Result Codes, Execution Time, Implementation if there are differences between the reference version and the
operation defined in this standard.
5.2.1. TIA/EIA-602-A Action Commands
The following action commands are defined in TIA/EIA-602-A, Section 6.1. This section describes, for each action
command, any modifications or extensions to command behavior necessary for compliance to this standard.
Description of the T, P, Z, &C, &D, &F and I commands are unchanged, see TIA/EIA-602-A.
This section includes both normative and informative information useful for mapping action commands to WDS types
other than the GSTN. Refer to Section 5.3 of this standard for additional information.
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TIA-678-A
5.2.1.1. Dial
Syntax
D[<dial string>][;]
Description
The operation of this command is modified from the description given in TIA/EIA-602-A Section 6.1.1, as follows. The
operation described in this standard is meant to be a permissive generalization of the behavior specified in TIA/EIA-602A for GSTN modems. It is not meant to imply a preferred implementation, or to constrain implementation in any way.
Refer to Section 5.3 of this standard for additional information.
This command instructs the ACE to issue (using interface I2 of Figure 4) a request that the DCU originate an on-line
data state session. The ACE passes <dial string> to the DCU as a parameter of the request.
The DCU must either grant or deny the request issued by the ACE, and must signal grant or denial by passing a result
code to the ACE (using interface I2 of Figure 4). The DCU must ignore characters appearing in the <dial string> which
the DCU does not recognize as a valid part of the call addressing or navigation information for the selected WDS-Side
Stack.
The interpretation of the <dial string> and any steps taken by the ACE and DCU to originate an on-line data state
session may be manufacturer-specific or network-specific. For example:
(1)
The DCU may immediately deny the request and return an ERROR result code if it is unable to initiate
an on-line data state session (e.g. it is already in On-Line Data State).
(2)
The DCU may interpret sequences of characters (using manufacturer-specific or network-specific
formats and delimiters), in addition to individual characters, as dial modifiers or call addressing
information.
(3)
The DCU may ignore unrecognized sequences as a unit, in addition to ignoring unrecognized individual
characters, in the <dial string>.
(4)
The DCU may attempt to initiate an end-to-end connection across the currently selected WDS type
(using the currently selected WDS-Side Stack), using the <dial string> as address and navigation
information, and may return a result code determined by the success or failure of the connection attempt.
(5)
The DCU may immediately grant the request and return a CONNECT result code if permitted by the
combined interpretation of the <dial string>, the selected WDS-Side Stack, and the selected DTE-Side
Stack - for example, to indicate successful connection to a DCE-based “network gateway” (e.g. a VRES
as described in Section 3.5.1 of this standard).
(6)
The DCU may grant the request specifying a different DTE-to-DCE data rate to the ACE than the one in
effect immediately prior to commencement of execution of the dial command.
(7)
The ACE may defer processing of the <dial string> (e.g. call signaling) when the dial command is
terminated by a semicolon, provided the DCE meets the requirements set forth in Section 6 and Section
5.3 of this standard.
This list is not meant to be exhaustive, or to imply a preferred implementation.
Upon receiving a denial and result code, the ACE must issue the result code to the DTE at the DTE-DCE data rate in
effect immediately prior to commencement of execution of the dial command. The DTE must remain in Command State,
responsive to that data rate.
Upon receiving a grant and result code, the ACE must issue the result code to the DTE at the DTE-DCE data rate in
effect immediately prior to commencement of execution of the dial command. Subsequent action by the DCE depends
on the format of the command line:
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TIA-678-A
(1)
If the <dial string> is not followed by a semicolon, the DCE must enter On-Line Data State using the
currently selected DTE-Side Stack and WDS-Side Stack and the data rate indicated by the DCU’s result
code.
(2)
If the <dial string> is followed by a semicolon, the DCE must enter On-Line Command State using the
currently selected WDS-Side Stack and the data rate indicated by the DCU’s result code.
Refer to Section 5.2.1.2 for information about dial modifiers.
Note: It is recommended that the WDS-Side Stack respect the settings of parameters X, S6, S7, S8 when processing
the <dial string>. For example, any of the commands {X, X0, X1, X3} disable dial tone detection, and enable a delay
based on the value of S6. The DCE might respect the setting of S6 by at least executing a no-op delay loop for the
appropriate interval +/- 10%. This allows the DCE to satisfy call set-up timing constraints intentionally introduced by the
DTE. This recommendation is not intended to diminish normative provisions of TIA/EIA-602-A or other applicable
standards with respect to X, S6, S7, S8.
5.2.1.2. Dial Modifiers
The following characters and character sequences may appear within a <dial string>, in any order or combination.
Interpretation of the <dial string> may be manufacturer-specific or network-specific, except where TIA/EIA-602-A
describes mandatory behavior for the GSTN WDS type or mandatory behavior independent of WDS type.
Note: Although this standard permits manufacturer-specific and network-specific dial modifiers, it is recommended that
the DCE recognize only the dial modifiers described in this section. Some DTE applications reformat dial strings before
passing them to the DCE. This reformatting may include insertion of space characters or other delimiters, and deletion
of fields which the DTE application determines are redundant or meaningless based on embedded assumptions that the
WDS type is GSTN.
The section summarizes all mandatory and optional DCE dial modifiers specified in this standard. All mandatory dial
modifiers in this table are part of the Common AT Command Set, and must be accessible in all DCE operating modes
(except On-Line Data State). This standard does not define any dial modifiers other than those defined in TIA/EIA-602A.
The columns of the summary table (below) are interpreted as follows:
Dial Modifier
The syntax of the dial modifier. Square brackets (e.g. [n]) represent syntax modifiers
which may be used at the option of the DTE.
Req.?
An X in this column indicates that the DCE must recognize the syntax in the Dial Modifier
column. The entry is blank for optional dial modifiers.
Reference
Identifies the reference document which provided the definition of the dial modifier used in
this standard.
Summary
A brief description of dial modifier operation and side-effects.
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Table 2 - Dial Modifiers
Dial Modifier
01234
56789
*#ABCD
Req Reference
?
X
TIA/EIA-602A
TIA/EIA-602A
,
X
T
X
P
X
!
W
TIA/EIA-602A
TIA/EIA-602A
TIA/EIA-602A
TIA/EIA-602A
TIA/EIA-602A
@
Summary
Used individually within call addressing sequences.
Used individually within call addressing and network navigation
sequences. Required only if DTMF address signaling supported for the
current WDS type.
(comma, ASCII 2C hex) Pause for preset interval during address
signaling.
Use DTMF address signaling. The DCE may ignore this modifier if
DTMF address signaling is not supported for the current WDS type.
Use pulse address signaling. The DCE may ignore this modifier if
pulse address signaling is not supported for the current WDS type.
(exclamation point, ASCII 21 hex) Causes the ACE to go on-hook for a
specified interval, then go off-hook, pause, and continue processing
the dial string. Required only for GSTN WDS type.
Causes the ACE to listen for dial tone before continuing processing the
dial string. Required only for GSTN WDS type.
(at sign, ASCII 40 hex)Causes the ACE to listen for remote ringing,
followed by 5 seconds of silence, before continuing processing the dial
string. Required only for GSTN WDS type.
5.2.1.2.1. Dialing Digits
Syntax
A string of zero or more of the characters:
0123456789ABCD*#
Description
As described in TIA/EIA-602-A. The interpretation of these dial modifiers may be manufacturer-specific or networkspecific for non-GSTN applications.
Note: it is recommended that each WDS-Side Stack define an address representation for use in the <dial string> which
assigns meaning only to dialing digits, for reasons described in section 5.2.1.2.
5.2.1.2.2. Pause During Dialing
Syntax
,
(comma, ASCII 2C hex)
Description
As described in TIA/EIA-602-A. The interpretation of this dial modifier may be manufacturer-specific or network-specific
for non-GSTN applications.
Note: It is recommended that the WDS-Side Stack respect the setting of parameter S8 when processing this dial
modifier in the <dial string>, by at least executing a no-op delay loop for the appropriate interval +/- 10%. This allows
the DCE to satisfy call set-up timing constraints intentionally introduced by the DTE. This recommendation is not
intended to diminish normative provisions of TIA/EIA-602-A or other applicable standards with respect to S8.
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5.2.1.3. Incoming Call Indication
The Incoming Call Indication is an unsolicited result code.
Syntax
RING
2
(alphabetic form)
(numeric form)
Description
The operation of this result code is modified from the description given in TIA/EIA-602-A Section 6.1.4, as follows. The
operation described in this standard is meant to be a permissive generalization of the behavior specified in TIA/EIA-602A for GSTN modems. It is not meant to imply a preferred implementation, or to constrain implementation in any way.
Refer to Section 5.3 of this standard for additional information.
This unsolicited result code indicates that the currently selected WDS-Side Stack has issued (via the DCU or
equivalent) a request to the ACE to accept an unsolicited on-line data state session.
The ACE must either grant or deny the request from the DCU. The ACE must signal grant or denial to the DCU (using
interface I2 of Figure 4). In the event of a grant, the DCU must return a session status indication to the ACE, indicating
whether session set-up using the selected WDS-Side Stack succeeded or failed, and what DTE-DCE data rate to use
on On-Line Data State. The ACE then reports the session status to the DTE and enters On-Line Data State.
The action taken by the ACE in response to the request by the DCU depends on the current operating state of the DCE
and the setting of parameter S0. Operation in On-Line Command State and On-Line Data State is manufacturerspecific. Operation in Command State is as follows (assuming that no manufacturer-specific criteria prohibit the DCE
from accepting calls):
(1)
If transmission of result codes is not suppressed, the ACE must transmit a RING unsolicited result code
to the DTE on logical circuit RD to signal the connection request. For purposes of other provisions of this
standard, RING result codes transmitted on logical circuit RD do not constitute ring indications.
(2)
The ACE must transmit an active pulse to the DTE on logical circuit RI to signal the connection request .
For purposes of other provisions of this standard, each active pulse on logical circuit RI constitutes a ring
indication.
(3)
The ACE must respond to an answer command (received from the DTE on logical circuit TD) by granting
the most recently signaled DCU request, provided that the request has not been canceled by the DCU.
Refer to Section 5.2.1.6 for additional information.
(4)
If the value of parameter S0 is non-zero, the ACE must automatically grant the most recently transmitted
DCU request (if it has not been canceled) after the number of ring indications equal to the value of
parameter S0.
(5)
Upon granting a request and receiving a session status indication that the session was established , the
ACE must transmit a CONNECT (or equivalent) result code to the DTE using the last data rate in effect.
The ACE then places the DCE in On-Line Data State using the selected DTE-Side Stack and WDS-Side
Stack, at a data rate specified by the DCU.
(6)
Upon granting a request and receiving a session status indication that the session was not established ,
the ACE must transmit a network-specific result code to the DTE using the last data rate in effect. The
ACE must remain in Command State, using the last data rate in effect.
Note 1: The DCU (or equivalent) may cancel a request at any time before it is granted, and may return an error status to
the ACE if it is unable to establish a session in response to a grant. Any steps taken by the ACE, DCU, and WDS to
execute the request-grant/deny-status sequence described above may be manufacturer-specific or network-specific.
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TIA-678-A
Note 2: It is recommended that the DCE match the operation of the RING result code defined in Section 6.1.4 of
TIA/EIA-602-A and applicable national telephony standards and regulations as closely as possible for all WDS types.
Note 3: It is recommended that the WDS-Side Stack respect the setting of parameter S7 when manually or
automatically accepting unsolicited requests for on-line data state sessions. This allows the DCE to satisfy call set-up
timing constraints intentionally introduced by the DTE. This recommendation is not intended to diminish normative
provisions of TIA/EIA-602-A or other applicable standards with respect to S7.
Implementation
The DCE must implement this result code for all supported WDS types which define procedures for issuing and
accepting unsolicited connection requests (or equivalent).
5.2.1.4. Answer
Syntax
A
Description
The operation of this command is modified from the description given in TIA/EIA-602-A Section 6.1.5, as follows. The
operation described in this standard is meant to be a permissive generalization of the behavior specified in TIA/EIA-602A for GSTN modems. It is not meant to imply a preferred implementation, or to constrain implementation in any way.
Refer to Section 5.3 of this standard for additional information.
This command instructs the ACE to immediately grant any outstanding request from the DCU to accept an unsolicited
on-line data state session. Such a request becomes outstanding when the selected WDS-Side Stack receives a
connection request (or equivalent) from the WDS.
The ACE must either grant or deny the request from the DCU. The ACE must signal grant or denial to the DCU (using
interface I2 of Figure 4). In the event of a grant, the DCU must return a session status indication to the ACE, indicating
whether session set-up using the selected WDS-Side Stack succeeded or failed, and what DTE-DCE data rate to use
on On-Line Data State. The ACE then reports the session status to the DTE and enters On-Line Data State.
The action taken by the ACE in response to this command depends on the current operating and connection state of
the DCE. Operation in On-Line Command State and On-Line Data State is manufacturer-specific. Operation in
Command State is as follows (assuming that no manufacturer-specific criteria prohibit the DCE from accepting calls):
(1)
If no request is outstanding, or all previously outstanding requests have been canceled by the DCU, the
ACE must issue a result code and remain in Command State at the most recent effective DTE-DCE data
rate. The result code issued may be one of those described in Section 6.1.5 of TIA/EIA-602-A, or some
other manufacturer-specific or network-specific result code.
(2)
If a request is outstanding, the ACE must grant the request (via interface I2). The DCU must then issue a
session status indication to the ACE.
(3)
Upon granting a request and receiving a session status indication that the session was established , the
ACE must transmit a CONNECT (or equivalent) result code to the DTE using the last data rate in effect.
The ACE then places the DCE in On-Line Data State using the selected DTE-Side Stack and WDS-Side
Stack, at a data rate specified by the DCU.
(4)
Upon granting a request and receiving a session status indication that the session was not established ,
the ACE must transmit a network-specific result code to the DTE using the last data rate in effect. The
ACE must remain in Command State, using the last data rate in effect.
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TIA-678-A
Note 1: The DCU (or equivalent) may cancel a request at any time before it is granted, and may return an error status to
the ACE if it is unable to establish a session in response to a grant. Any steps taken by the ACE, DCU, and WDS to
execute the request-grant/deny-status sequence described above may be manufacturer-specific or network-specific.
The DCE must ignore any additional commands that appear after A on the same command line.
Note 2: It is recommended that the WDS-Side Stack respect the setting of parameter S7 when processing this
command. This allows the DCE to satisfy call set-up timing constraints intentionally introduced by the DTE. This
recommendation is not intended to diminish normative provisions of TIA/EIA-602-A or other applicable standards with
respect to S7.
5.2.1.5. Hook Control
Syntax
H
H0
(disconnect from line and terminate call)
(disconnect from line and terminate call)
Description
The operation of this command is modified from the description given in TIA/EIA-602-A Section 6.1.6, as follows. The
operation described in this standard is meant to be a permissive generalization of the behavior specified in TIA/EIA-602A for GSTN modems. It is not meant to imply a preferred implementation, or to constrain implementation in any way.
Refer to Section 5.3 of this standard for additional information.
This command instructs the ACE to issue a session termination request for the selected WDS-Side Stack to the DCU
(or equivalent). The DCU must either grant or deny the request, and must return a status indication to the ACE. The
ACE must transmit the status indication to the DTE as a result code.
Any steps taken by the ACE, DCU, and WDS to terminate a session may be manufacturer-specific or network-specific.
5.2.1.6. Return to On-Line Data State
Syntax
O
O0
O<value>
(return to on-line data state)
(return to on-line data state)
(manufacturer-specific)
Description
As described in TIA/EIA-602-A.
The DCE returns to On-Line Data State using the currently selected DTE-Side Stack and WDS-Side Stack. Any steps
taken by the ACE, DCU, and WDS to process this command may be manufacturer-specific or network-specific.
5.2.2.
ACE/DTE Interface Parameters
The commands defined in 6.2/TIA/EIA-602-A and in V.250 are also applicable to DCE conforming to this standard, with
the same definitions. The DCE identification commands defined in V.250 are applicable to wireless DCE.
5.2.3.
ACE Parameters
The commands defined in 6.3/TIA/EIA-602-A for ACE control are also applicable to some classes of wireless DCE.
Where used, the definitions are unchanged.
For Analog Cellular DCE, the commands defined in V.250 are applicable, with the definitions unchanged.
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TIA-678-A
5.2.4.
Wireless DCE Extended Commands and Parameters
The following additional commands and parameters control the operation of the ACE and DCU outside the scope of
TIA/EIA-602-A or V.250.
The primary purpose of the additions is to provide means for a DTE to determine and selectively activate capabilities of
the DCE, including selection among various WDS types and DTE-DCE protocols. The DCE must recognize all
commands defined in this section in all variants of Command State and On-Line Command State (e.g., regardless of
the setting of mandatory parameter +WS46, optional parameter +FCLASS, or other parameters).
This section includes both normative and informative information.
5.2.4.1. Compliance Indication
Syntax
+W
+W=?
(display which wireless DTE control standards are supported)
(test whether +W supported)
Description
This command allows the DTE to determine whether or not the DCE acknowledges support of the +W commands
defined in this and related standards, and which wireless DCE control standards the DCE supports.
A DCE which supports the +W command must return an OK result code in response to +W=?; any DCE which does not
support the +W command will return an ERROR result code.
A DCE which complies with this standard must respond to +W by transmitting a list of strings enclosed in double quotes
to the DTE, followed by an OK result code (i.e. as if +W were an action command outputting information text enclosed
in quotes). The list of strings must include the string “101” , and may include other strings specified by other wireless
DCE control standards or annexes. If the DCE supports more wireless DCE control Standards and Annexes than can
be expressed on a single line of information text, each line except the last ends with a comma to indicate that another
line follows.
Strings associated with Annexes to this standard have the form “+W<text>“, where <text> is Annex-specific. The DCE
must transmit strings associated with Annexes to this standard after transmitting the string “101”, but before
transmitting any strings associated with standards other than this standard and its Annexes. Refer to each Annex for
additional information. Any DCE supporting Annex B will return string "+WCXF". Any DCE supporting Annex C will
return string "+WCXI". Any DCE supporting Annex D will return string "+WCXD".
Any DCE which does not comply with this standard must return either an ERROR result code (if no other wireless DCE
control standards are supported), or a list of strings followed by OK which must not include the string “101” (if other
wireless DCE control standards are supported).
Example Responses:
A DCE supporting this standard, but no other wireless DCE control standards or Annexes, returns:
“101”
OK
in response to +W.
A DCE supporting this standard and Annex B defining its identification string as “+WCXF”, but no other Annexes,
returns:
“101”,”+WCXF”
OK
A DCE supporting this standard and the same Annex B, and a future wireless DCE control standard 999, but no other
wireless DCE control standards or Annexes, returns either:
“101”,”+WCXF”,”999”
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TIA-678-A
OK
or
“999”,“101”,”+WCXF”
OK
If the DCE supports more standards than can be expressed on a single line of information text, each line except the last
ends with a comma to indicate that another line follows.
-end of quoted material, no more changes proposedThis command may not be aborted.
Result Codes
OK
ERROR
The DCE claims compliance with at least one standard.
The DCE does not acknowledge compliance with any standard.
Execution Time
Execution time is dependent on the time required to transmit the list of strings and result code to the DTE.
Implementation
Implementation of this command is mandatory. Implementation of at least the string “101” is mandatory.
Implementation of exactly one unique string having the form “+W<text>“ is mandatory for each supported Annex to this
standard.
Note: It is recommended that the string associated with a given Annex to this standard be the name of the command
which reports which other commands defined by that Annex are supported by the DCE. Refer to Section 8, “Building on
This Standard”, for additional information.
5.2.4.2
DTE-Side Stack Selection
Parameter Syntax
+WS45=[n]
+WS45?
+WS45=?
(set DTE-Side Stack)
(display current DTE-Side Stack)
(display valid DTE-Side Stack options)
Description
This parameter selects or indicates the DTE-Side Stack to be used by the DCE the next time it enters On-Line Data
State. The DCE need not permit changing the value of +WS45 from On-Line Command State. Refer to Figures 2, 3,
and 6 in Section 3 of this standard for definitions and reference models describing the DTE-Side Stack.
The DCE must not change the set of valid AT commands (i.e. commands defined at either interface I 4 or interface I5 of
Figure 5) in response to the setting of +WS45.
If the DCE implements the +FCLASS parameter, the DCE may ignore the setting of +WS45 for +FCLASS settings
other than +FCLASS=0.
Note: This standard establishes a hierarchical relationship among parameters which affect the DCE operating mode. In
the event of a conflict between DCE settings related to the value of these parameters, the DCE settings required by
+WS46 and +FCLASS take precedence over those required by +WS45. The procedure used by the DCE to resolve
conflicts may produce side effects in command execution or parameter values. Refer to Section 5.4 of this standard for
additional information.
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Defined Values
+WS45
Code
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
100-199
200-255
Description
Transparent
Character Stream
Reliable Transparent
Character Stream
Table 3 - DTE-Side Stack Selection values
Remarks
Operation of the Transparent Character Stream is defined in this
standard. It provides character-based data service between the DTE
and a remote station addressed by the dial string, with unbounded
latency and error rate.
This service may use a DCE-based Packet Assembler / Disassembler
(PAD). Internal operation is manufacturer-specific.
Operation of the Reliable Transparent Character Stream is defined in
this standard. It provides character-based data service between the
DTE and a remote station addressed by the dial string, with bounded
latency and error rate.
This service may use a DCE-based Packet Assembler / Disassembler
(PAD). Internal operation is manufacturer-specific.
Common Packet
Reserved for future definition . The Common Packet Protocol is
Protocol (CPP)
envisioned as a frame-based DTE-DCE protocol providing WDSindependent syntax and semantics to support concurrent multi-function
operation of the DCE. The Common Packet Protocol is a topic of
ongoing research and development.
SLIP
Serial Link IP datagram service (generally, a datagram tunneling
service).
PPP
PPP datagram encapsulation (generally, a datagram tunneling service).
Telnet
Reliable virtual circuit service with Telnet (TCP/IP) pad configuration
commands.
X.28 PAD
Reliable virtual circuit service with X.3 PAD configuration commands.
ISDN
Reserved for standards-based interface to proposed ISDN networks.
Native Mode
Requested on behalf of World Wide DataTAC Operator’s Group
MASC 1
Requested on behalf of Mobitex Operator’s Association
MASC 2
Requested on behalf of Mobitex Operator’s Association
Pinpoint Proprietary
Requested by Pinpoint Communications
Device Programming Requested by McCaw Cellular Communications / Rockwell International
Interface
Metricom Proprietary Requested by Metricom, Inc.
Hayes Proprietary
Requested by Hayes Microcomputer Products
(AutoStream)
Hayes Proprietary
Requested by Hayes Microcomputer Products
(AutoSync)
IBM Proprietary
Requested by IBM
PCSI Proprietary
Requested by PCSI
Unknown /
These codes should be used by DCE which implement manufacturerExperimental
specific DTE-Side Stacks not listed above.
(Manufacturerspecific)
Unknown /
These codes should be used by DCE which implement network-specific
Experimental
DTE-Side Stacks not listed above.
(Network-specific)
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+WS45
Code
Other
Description
Remarks
TBD
All other +WS45 codes are reserved for future allocation.
NOTE: For non-experimental DTE-Side Stacks not listed here,
implementers are strongly encouraged to request assignment of a
+WS45 code.
Recommended Default Setting
Any default setting may be used, with the provision that the default setting must satisfy the requirements for characterstream operation given in Section 6.2 of this standard.
Implementation
Implementation of this parameter is mandatory. Implementation of at least one value satisfying the requirements for
character-stream operation given in Section 6.2 of this standard is mandatory.
5.2.4.3
WDS-Side Stack Selection
Parameter Syntax
+WS46=[n]
+WS46?
+WS46=?
(set WDS-Side Stack)
(display current WDS-Side Stack)
(display valid WDS-Side Stack options)
Description
This parameter selects or indicates the WDS-Side Stack (which comprises both a WDS type and DCE-WDS
communication protocols) to be used by the DCE in all operating states. Any procedures needed to change from the old
to the new WDS-Side Stack must complete prior to generation of the OK result code. The DCE need not permit
changing the value of +WS46 from On-Line Command State. Refer to Figures 2, 3, and 6 in Section 3 of this standard
for definitions and reference models describing the WDS-Side Stack.
Note: This standard establishes a hierarchical relationship among parameters which affect the DCE operating mode. In
the event of a conflict between DCE settings related to the value of these parameters, the DCE settings required by
+WS46 take precedence over those required by +WS45 and +FCLASS. The procedure used by the DCE to resolve
conflicts may produce side effects in command execution or parameter values. Refer to Section 5.4 of this standard for
additional information.
Defined Values
Table 4 - Wireless Data Service-Side Stack selections
+WS46
Code
0
Description
Remarks
Reserved
This value is reserved for use by commands which need to designate
“no selected WDS type”.
If implemented, enables standard voice / data FAX modem behavior
(typically over land lines)
1
GSTN (telephone)
2
3
4
5
Mobitex
DataTAC
CDPD
One-Way Numeric
Paging
ARDIS
6
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+WS46
Code
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
240-255
Other
Description
AMPS Analog
Cellular - Data Mode
One-Way Alpha
Paging
Pinpoint ARRAY
Metricom
Inmarsat
GSM Digital Cellular
CDMA Digital
Cellular
TDMA Digital
Cellular
Multiple Concurrent
WDSs
Reserved.
AMPS Analog
Cellular - Voice
Mode
Wireline Voice Mode
PCSI Host Packet
Interface
Personal Digital
Cellular (PDC) High
Speed
N star (Japanese
Mobile Satellite
Service)
W-CDMA
Personal Handyphone System
(PHS)
CdmaOne (Japan)
IMT-2000
Multi-Mode
PDC packet mode
Experimental /
Unknown /
Unregistered
TBD
Remarks
This setting is reserved for use in conjunction with values of +WS45
that support concurrent access to two or more WDSs.
This setting is reserved for proposed ISDN networks.
These codes should be used by DCE which implement manufacturerspecific WDS-Side Stacks not listed above.
All other +WS46 codes are reserved for future allocation.
NOTE: For non-experimental network types not listed here,
implementers are strongly encouraged to request assignment of a
+WS46 code.
Recommended Default Setting
Any default setting may be used, with the provision that the default setting must be compatible with a default setting of
+WS45 which satisfies the requirements for character-stream operation given in Section 6.2 of this standard.
Implementation
Implementation of this parameter is mandatory. Implementation of at least one non-zero value is mandatory.
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TIA-678-A
If implemented, the interpretation of +WS46=1 may be manufacturer-specific.
5.2.4.4
Service Class Selection
Syntax
+FCLASS=n
+FCLASS=?
(set service class)
(display valid service class options)
Description
This optional command is defined in other standards. Refer to TIA/EIA-578-B, TIA/EIA-592-A and ITU-T V.253 for
additional information. The definition provided in this standard is based on that used in ITU-T V.253.
This parameter selects a DCE service class: data, facsimile, or voice. The DCE shall recognize the value of 0 as the
data mode described in this standard.
As part of the WDS-Side Stack session setup procedures described in Section s 5.2.1.1, 5.2.1.5, 5.2.1.6, and 7 of this
standard, the DCE may automatically switch to various modes, changing the value of +FCLASS.
The DCE may enable or disable commands in the selected WDS-Specific AT Command Set (i.e. commands defined at
interface I5 of Figure 5) in response to the setting of +FCLASS. The DCE must not enable or disable commands in the
Common AT Command Set (i.e. commands defined at interface I4 of Figure 5) in response to the setting of +FCLASS,
but may ignore the setting of +WS45 for +FCLASS settings other than +FCLASS=0.
Note: :
The +FCLASS action command was defined in standards prior to ITU-T V.250, and does not follow the rules for display
of valid options established in ITU-T V.250. The DCE response to +FCLASS=? consists of a string of comma-separated
values, which must not be enclosed in parenthesis or quotes and which must be fully enumerated by the DCE (the DCE
must not use hyphens to indicate ranges). Some values accepted by +FCLASS include embedded period (ASCII 2E
hex) characters. All values accepted by +FCLASS are entered and displayed using the ITU-T V.250 rules for numeric
(rather than text) action command parameter values.
Note: This standard establishes a hierarchical relationship among parameters which affect the DCE operating mode. In
the event of a conflict between DCE settings related to the value of these parameters, the DCE settings required by
+FCLASS take precedence over those required by +WS45, but may be overridden by settings required by +WS46. The
procedure used by the DCE to resolve conflicts may produce side effects in command execution or parameter values.
Refer to Section 5.4 of this standard for additional information.
Abortability
This command may not be aborted.
Defined Values
0
1
1.0
2
2.0
3-7
8
9-15
16-255
Data mode (TIA/EIA-602-A, ITU V.250, TIA/IS-707-A, TIA-136)
Service Class 1 (TIA/EIA-578-B Facsimile Mode)
Service Class 1 (ITU T.31)
Manufacturer specific (typically a facsimile mode)
Service Class 2 (TIA/EIA-592-A, ITU T.32, TIA/IS-707-A, TIA-136 Facsimile Mode)
Reserved by TIA for other facsimile modes
Voice mode (ITU-T V.253)
Reserved by TIA for other voice modes
Reserved by TIA for future standardization
Default Setting
0
Data mode
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TIA-678-A
Implementation
Implementation of this command is optional.
If the DCE implements +FCLASS, the default setting must be +FCLASS=0 to satisfy the requirements for characterstream operation presented in Section 6.2.
5.3. Result Codes
This standard uses the result codes defined in Table 1, Section 5.5.1, TIA/EIA-602-A. This standard also defines
numeric codes defined for several CONNECT <text> result codes.
TIA/EIA-602-A defines three ways in which result codes are used:
(1)
As final result codes, which indicate the completion of a full ACE action and a willingness to accept new
commands from the DTE;
(2)
As intermediate result codes, which report on the progress of an ACE action; and
(3)
As unsolicited result codes, which indicate the occurrence of an event not directly associated with the
issuance of a command from the DTE.
The DCE issues exactly one final result code for each command line executed. The DCE may also issue unsolicited
result codes and intermediate result codes in response to conditions detected internally.
Each result code defined in TIA/EIA-602-A includes an alphabetic form and a numeric form. The DCE must implement
both forms, must issue the alphabetic form for a setting of V1, and must issue the numeric form for a setting of V or V0.
This standard does not define any extended result codes (i.e. result codes beginning with +). Annexes of this standard
may define extended result codes. Extended result codes have only an alphabetic form, which is returned regardless of
the setting of the V parameter. Refer to ITU-T V.250 for additional information.
The interpretation of some result codes is modified from the description given in TIA/EIA-602-A, as follows. The
interpretation described in this standard is meant to be a permissive generalization of the behavior specified in TIA/EIA602-A for GSTN modems. It is not meant to imply a preferred implementation, or to constrain implementation in any
way.
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Result Code
Table 5 - Result Codes
reference Description
OK
Numeric
Equivalent
0
CONNECT
1
5.3.1
RING
2
5.3.2
NO CARRIER
3
5.3.3
ERROR
4
CONNECT 1200
5
5.3.1
NO DIALTONE
6
5.3.4
BUSY
7
5.3.5
NO ANSWER
8
5.3.6
CONNECT 2400
10
5.3.1
CONNECT 4800
11
5.3.1
CONNECT 9600
12
5.3.1
Acknowledges execution of all commands on a command
line.
The ACE is moving from Command State to On-Line Data
State, using the current DTE-DCE data rate.
The currently selected WDS-Side Stack has issued a
request to the ACE to accept an unsolicited on-line data
state session.
A previously established connection has terminated, or a
connection could not be established during a dial, answer,
on-line, or auto-answer procedure.
Command not recognized, command line maximum length
exceeded, parameter value invalid, or other problem with
processing the command line.
The ACE is moving from Command State to On-Line Data
State, using a DTE-DCE data rate of 1200 bits/s.
A dial command failed because the selected WDS-Side
Stack could not obtain service from the WDS.
A dial command failed because the selected WDS-Side
Stack could not establish a connection with the addressed
remote station due to the number of sessions already in
progress, either within the remote station or within the
WDS.
A dial command failed because the WDS or remote station
behavior specified by the “@” dial modifier did not occur.
The ACE is moving from Command State to On-Line Data
State, using a DTE-DCE data rate of 2400 bits/s.
The ACE is moving from Command State to On-Line Data
State, using a DTE-DCE data rate of 4800 bits/s.
The ACE is moving from Command State to On-Line Data
State, using a DTE-DCE data rate of 9600 bits/s
5.3.1 Connection Indication
Description
This group of result codes signals the DTE that a connection or session has been established, and that the ACE is
moving from Command State to On-Line Data State. Each is always either an unsolicited result code (i.e. auto-answer
indication) or an intermediate result code (in response to a dial, on-line, or answer command).
Forms other than CONNECT or 1 indicate a data rate. Manufacturer-specific settings may alter the interpretation of the
data rate. In the absence of such manufacturer-specific settings, the result code indicates the rate at which the DCE will
operate in on-line data state.
The CONNECT and 1 forms imply that the most recent DTE-DCE data rate will be used in on-line data state.
The interpretation of these result codes may depend on the currently selected DTE-Side Stack (parameter +WS45) and
WDS-Side Stack (parameter +WS46). The result code may indicate that the DCE has established an end-to-end
connection, or it may indicate that the DTE has established a connection to a DCE-based “network gateway” (e.g. a
VRES as described in Section 3.5.1 of this standard).
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Implementation
Implementation of the CONNECT and 1 forms is mandatory. Implementation of other forms in this group is mandatory
for each supported data rate. The DCE need not implement any data rates other than those required by TIA/EIA-602-A.
5.3.2 Incoming Call Indication
Description
This result code indicates that the currently selected WDS-Side Stack has issued a request to the ACE to accept an
unsolicited on-line data state session. This result code is always an unsolicited result code.
Refer to Section 5.2.1.3 of this standard for additional information.
Implementation
Implementation of this result code is mandatory.
5.3.3. No Received Line Signal
Description
This result code indicates that a previously established connection has terminated, or that a connection could not be
established during a dial, answer, on-line, or auto-answer procedure. This result code is always a final result code.
The interpretation of this result code may depend on the currently selected DTE-Side Stack (parameter +WS45) and
WDS-Side Stack (parameter +WS46).
Refer to TIA/EIA-602-A, Section 6.2.7, for additional information.
Implementation
Implementation of this result code is mandatory.
5.3.4. No Dial Tone
Description
This result code indicates that a dial command failed because the selected WDS-Side Stack could not obtain service
from the WDS. This result code is always a final result code.
The interpretation of this result code may depend on the currently selected DTE-Side Stack (parameter +WS45) and
WDS-Side Stack (parameter +WS46).
Refer to TIA/EIA-602-A, Section 6.2.7, for additional information.
Implementation
Implementation of this result code is mandatory for all WDS types which could deny service to the DCE.
5.3.5. Remote Station Busy
Description
This result code indicates that a dial command failed because the selected WDS-Side Stack could not establish a
connection with the addressed remote station due to the number of sessions already in progress, either within the
remote station or within the WDS. This result code is always a final result code.
The interpretation of this result code may depend on the currently selected DTE-Side Stack (parameter +WS45) and
WDS-Side Stack (parameter +WS46).
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Refer to TIA/EIA-602-A, Section 6.2.7, for additional information.
Implementation
Implementation of this result code is mandatory for all WDS types on which the WDS or remote station could be “busy”.
5.3.6. No Quiet Answer
Description
This result code indicates that a dial command failed because the WDS or remote station behavior specified by the “@”
dial modifier did not occur. This result code is always a final result code.
The interpretation of this result code may depend on the currently selected DTE-Side Stack (parameter +WS45) and
WDS-Side Stack (parameter +WS46).
Refer to TIA/EIA-602-A, Section 6.1.1.7, for additional information.
Implementation
Implementation of this result code is mandatory for all WDS types which recognize the “@” dial modifier in a <dial
string>.
5.4. Parameter and Command Scope Rules
This section uses terms first defined in Section 3.8 of this standard.
5.4.1. Scope, Visibility, and Volatility Restrictions
All DCE parameters controlled by AT commands in the Common AT Command Set (ref. Figure 5) must have
unrestricted visibility and global scope, unless other visibility or scope is defined explicitly in an applicable standard.
Some of these parameters may have unstable or stable volatility. All AT commands defined in this standard are, by
definition, in the Common AT Command Set. Annexes of this standard may define optional additions to the Common AT
Command Set.
All DCE parameters controlled by AT commands in WDS-Specific AT Command Sets (ref. Figure 5) may have
restricted or unrestricted visibility, must have (by definition) local scope, and may have stable or unstable volatility,
unless other visibility or scope is defined explicitly in an applicable standard. Annexes of this standard may define
optional WDS-Specific AT Command Sets.
All AT commands in the Common AT Command Set must be available to the DTE in any DCE operating mode which
comprises Command State or On-Line Command State.
For commands and result codes in the Common AT Command Set, a given combination of command name and
parameter or argument must behave similarly in all modes for which that combination of command name and
parameter or argument are valid, and a given numeric result code must have the same meaning in all DCE operating
modes.
5.4.2. Parameter Value Conflict Procedures
The scope, visibility, and volatility restrictions established in Section 5.4.1 of this standard are intended to decrease the
differences among DCE operating modes from the perspective of the DTE. Essentially, any commands that do not
control WDS-specific values become part of the Common AT Command Set and are available in all DCE operating
modes.
Some DCE operating modes are governed by other standards. These standards may define WDS-specific commands
which duplicate or resemble functionality of the Common AT Command Set. The syntax, and even the semantics, of
these commands may differ from syntax and semantics of commands in the Common AT Command Set, to a degree
that complicates translation from one command set to the other.
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Example: A DTE could establish a WDS-Specific value for a flow control parameter having global scope. The DTE could
then use +WS46 to request a different WDS type. The new WDS type might be governed by the global flow control
parameter, but might be unable to use its (now obsolete) WDS-specific value.
This section defines DTE and DCE conflict resolution procedures to be used in situations like the one given in the
example.
5.4.2.1. DCE Procedures
The Table specifies how the DCE must resolve conflicts. It specifies, for each parameter defined in this standard (left
column):
(1)
Center column: Other parameters that the DCE must always silently set to default values when the value
of the parameter in the left-hand column is changed;
(2)
Right column: Other parameters which may, depending on their current value, force the DCE to abort
command execution and issue an ERROR result code when an attempt is made to change the value of
the parameter in the left-hand column.
Table 6 - DCE Conflict Resolution Procedures
Rule
#
1
Parameter
Changed
+WS46
DCE Must Set to Default
2
+FCLASS
+WS45
NOTE: The DCE may ignore the
setting of +WS45 for non-zero
values of +FCLASS, but must set
+WS45 to a default value each
time +FCLASS is set to any value.
The default value of +WS45 may
be dependent on the value of
+FCLASS.
3
+WS45
4
flow control, port
rate, framing, logical
circuit configuration
(&C, &D)
other parameters
5
+WS45, +FCLASS
DCE May Block if New Setting Invalid
Given Current Setting Of
flow control, port rate, framing, logical
circuit configuration (&C, &D)
flow control, port rate, framing, logical
circuit configuration (&C, &D);
+WS46
flow control, port rate, framing, logical
circuit configuration (&C, &D);
+WS46, +FCLASS
flow control, port rate, framing, logical
circuit configuration (&C, &D);
+WS45, +FCLASS, +WS46
flow control, port rate, framing, logical
circuit configuration (&C, &D);
+WS45, +FCLASS, +WS46
5.4.2.2. DTE Procedures (Informative)
The DTE may avoid conflicts by using combinations of the following techniques:
(1)
Use only a single value of +WS45 and +WS46, initialized by the DTE at startup. Note that this does not
imply that only a single WDS type is used; annexes of this standard may permit concurrent multi-function
operation, in which +WS45 may select a “multi-drop” DTE-DCE protocol, while +WS46 may select a
protocol translator which handles several WDS types concurrently.
(2)
When using specialized settings of a parameter in the right column, set the parameter to its default value
before changing any corresponding parameters in the left column.
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(3)
After changing a parameter in the right column, reprogram parameters in the center column to desired
values.
Certain rare combinations of DCE operating mode and other parameter values might create a deadlock condition, in
which several parameter values reciprocally block execution of commands to change those values. In the event of
deadlock, the DTE can use the Z or &F command to break the deadlock.
5.4.2.3
Examples (Informative)
The following examples illustrate the application of recommended DTE procedures and the mandatory DCE scope,
visibility, volatility, and parameter conflict resolution procedures.
5.4.2.3.1
Example 1
The DCE is in some mode A (perhaps GSTN, Reliable Transparent Mode) using XON / XOFF flow control. The DTE
changes the DCE to some other mode B (perhaps ARDIS, Native Mode) and explicitly establishes RFR / CTS flow
control. The DTE then changes the DCE back to mode A. What flow control method is in force?
Assume that the DCE does not implement +FCLASS, and that mode A was established by the sequence:
AT+WS46=1;+IFC=1,1;+WS45=1
Then assume that mode B was established by the sequence:
AT+WS46=6;+IFC=2,2;+WS45=8
The change of +WS46 forces +WS45 to a default value (Rule #1). The changes to +IFC are accepted because they
are valid for the new setting of +WS46 and the default setting of +WS45 (Rule #4). The change to +WS45 is accepted
because it is valid for the new settings of +IFC and +WS46.
Next, the DTE changes the DCE back to mode A. Assume that the following sequence is used:
AT+WS46=1;+WS45=1
The change of +WS46 forces +WS45 to a default value (Rule #1). The DCE rejects this change and generates an
ERROR response if the current flow control settings are not valid for the combination of the default setting of +WS45
and the new setting of +WS46 (Rule #1). But what are the current flow control settings?
As stated in Section 5.4.1, the flow control parameters have global scope, unlimited visibility, and either stable or
unstable volatility. This means:
i)
Global Scope: There is only one “state variable” within the DCE to hold the current value of a given flow
control parameter, and this variable is used in all modes;
ii)
Unlimited Visibility: Every DCE operating mode supports commands to query and set flow control
parameters; and
iii)
Stable or Unstable Volatility: The DCE is permitted, but not required, to change the value of flow control
parameters during mode changes.
Therefore, the current flow control settings are either:
a) The settings in effect for mode B (that is, +IFC=2,2), or
b) Default settings (which may be either defaults specific to mode A, or global defaults)
The selection of either (a) or (b) is manufacturer-specific. Therefore, a DTE cannot know what the flow control settings
will be after a mode change, without additional information about the DCE implementation (i.e. as provided by +GMI?,
+GMM?, +GMR?).
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Note: :
It is recommended, to simplify interaction between the DTE and DCE, that flow control parameters controlled by +IFC
have stable volatility; in other words, that the DCE preserve flow control settings across mode changes as suggested in
(a) above.
5.4.2.3.2
Example 2
The DCE is in some mode B (as in Example 1). The DTE changes the DCE to mode A and explicitly establishes V.25
bis compliant behavior of RLSD and CTS. The DTE then attempts to change the DCE back to mode B, which does not
support V.25 bis compliant behavior of RLSD and CTS. What is the response from the DCE?
The parameters which control operation of RLSD and CTS (e.g. &C, +IFC) have global scope, unlimited visibility, and
either stable or unstable volatility. The implications are as in Example 1. In particular, the DCE may either:
a) Obey Rule #1 and Rule #3 (above), in which case the DCE generates an ERROR response to both +WS45 and
+WS46 until the conflicting settings of &C, +IFC are corrected; or
b) Force default settings of applicable parameters (which may be either defaults specific to mode B, or global defaults)
The selection of either (a) or (b) is manufacturer-specific. Therefore, a DTE cannot know whether the DCE will accept or
reject the command to change to mode B, without additional information about the DCE implementation (i.e. as
provided by +GMI?, +GMM?, +GMR?).
Note: It is recommended, to simplify interaction between the DTE and DCE, that DTE interface parameters controlled by
+IFC, &C, etc. have stable volatility; in other words, that the DCE enforce preservation of their settings across mode
changes as suggested in (a) above.
6. DATA STATE OPERATION (NORMATIVE)
6.1. +WS45 and +WS46 in On-Line Data State
Figure 2 in Section 3.5.1 of this standard models the On-Line Data State operation of the DCE as continuous
translation between two protocols (the DTE-Side Stack, and the WDS-Side Stack) as follows:
(1)
The DCE receives data (and possibly other in-band information) from the DTE using the protocols
defined by the DTE-Side Stack. The DCE forwards this data to the WDS (and ultimately to a remote
station) using the protocols and transmission medium defined by the WDS-Side Stack.
(2)
The DCE receives data (and possibly other in-band information) from the remote station, via the WDS,
using the protocols defined by the WDS-Side Stack. The DCE forwards this data to the DTE using the
protocols and transmission medium defined by the DTE-Side Stack.
The WDS-Side Stack may be manufacturer-specific and network-specific. This standard does not establish
requirements for the WDS-Side Stack, and does not presume a particular mode of network operation (e.g. packet
switched, circuit switched) or communication protocol. A DCE may incorporate more than one WDS-Side Stack. The
DTE may use the +WS46 parameter defined in this standard to select among available WDS-Side Stacks.
The DTE-Side Stack may be manufacturer-specific and network-specific, and a DCE may incorporate more than one
DTE-Side Stack. The DTE may use the +WS45 parameter defined in this standard to select among available DTE-Side
Stacks.
All DCE claiming compliance with this standard must provide a default DTE-Side Stack which satisfies the requirements
for character stream operation established in this standard. Other DTE-Side Stacks may present any desired protocol to
the DTE, including enhancements of character stream operation, frame-based protocols, and other protocols.
The definition of a DTE-Side Stack may include unique provisions for transitioning into Command State and On-Line
Command State from On-Line Data State. The &D1 command, if supported, must be honored for all settings of
+WS45.
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6.2. Requirements for Character Stream Operation
The protocol translation established by the default settings of +WS45 and +WS46, while operating with +FCLASS=0 (or
equivalent) in DCE compliant to this standard must meet or exceed the following criteria. These criteria need not apply
to other values of +WS45 or +WS46.
(1)
The DCE must automatically, upon power-up, select a DTE-Side Stack (+WS45) and compatible WDSSide Stack (+WS46) which satisfy all criteria in this section.
(2)
The DCE must select values of +WS45 and +WS46 in response to a Z command, and in response to an
&F command, which are identical to those selected upon power-up
(3)
After executing at most one initialization command line, consisting of at most 40 characters (which may
include commands not defined in TIA/EIA-602-A), the DCE must accept a dial command with a <dial
string> containing an address in a manufacturer-specific or network-specific format (which may be of
length 0 or more), and must attempt to establish a connection to the remote station or VReS identified by
the address expressed in or implied by the <dial string>.
(4)
If a connection cannot be established, the DCE must report a manufacturer-specific selection from the
list of supported result codes (e.g. NO CARRIER, BUSY) to the DTE.
(5)
Once a connection is established, the DCE must enter the On-Line Data State.
(6)
In On-Line Data State, the DCE must accept individual octets from the DTE. The DCE must forward
these octets (individually, or within dynamically assembled packets) across the above established
connection without the need for the DTE to transmit explicit delimiting octets or other handshake.
(7)
In On-Line Data State, the DCE must forward data received from the above established connection
(whether received as individual octets or as packets) to the DTE as individual characters, not enclosed in
any packet delimiters or other explicit handshake.
(8)
The combination of DCE and WDS need not preserve the order of transmitted data, and need not
transmit data error-free or loss-free, in each direction.
Note: It is strongly recommended that the average bit error rate for each direction of transmission, including any data
lost, spurious, or out-of-order, not exceed 10-3 over a 10,000 octet sample in each direction, measured between remote
station and DTE. This practice allows DTE-based applications to make useful assumptions about the class and quality
of service provided during character stream operation of a DCE.
(9)
The end-to-end transmission delay in each direction may be variable, and may be manufacturer-specific.
Note: It is strongly recommended that the average end-to-end delay per octet not exceed 15 seconds over a 10,000
octet sample in each direction measured between remote station and DTE. For octets transmitted by the DTE, the
measurement of the end-to-end delay for each octet begins when the DTE accepts the octet, and ends when the octet
is delivered to the remote station, to permit the use of flow control. This practice allows DTE-based applications to make
useful assumptions about the class and quality of service provided during character stream operation of a DCE.
(10)
The DTE must be able to terminate the above established connection using only TIA/EIA-602-A
commands (e.g. ATH).
6.3. Transparent Character Stream
The setting +WS45=0 designates a “Transparent Character Stream” DTE-Side Stack.
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Transparent Character Stream
A DTE-Side Stack capable of interworking with suitable WDS-Side Stacks to satisfy all
criteria stated in Section 6.2 of this standard. Selected by +WS45=0. DCE must satisfy all
criteria in Section 6.2, but need not implement +WS45=0.
Note: :
A manufacturer may implement any DTE-Side Stack which meets or exceeds this definition as +WS45=0. Setting
+WS45=0 does not assure interworking between DCE and WDS from different manufacturers, or between different
models from the same manufacturer.
6.4. Reliable Transparent Character Stream
The setting +WS45=1 designates a “Reliable Transparent Character Stream” DTE-Side Stack.
Reliable Transparent Character Stream
A DTE-Side Stack capable of interworking with suitable WDS-Side Stacks to satisfy all
criteria stated in Section 6.2 of this standard, and in addition providing in-order and errorfree delivery with an average BER of not more than 10-6 and an average end-to-end
delay of not more than 15 seconds per octet, each measured in both directions over a
200,000 octet sample. Selected by +WS45=1. DCE need not implement +WS45=1.
Note: :
A manufacturer may implement any DTE-Side Stack which meets or exceeds this definition as +WS45=1. Setting
+WS45=1 does not assure interworking between DCE and WDS from different manufacturers, or between different
models from the same manufacturer. A stack which meets the requirements for +WS45=1 also meets the requirements
for +WS45=0. Setting +WS45=1 assures the DTE of a well-defined interface to a useful and bounded quality of service.
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ANNEX A: BUILDING ON THIS STANDARD
This annex contains both informative and normative information. It establishes guidelines for the structure and content
of additional annexes. It reserves certain command and result code prefixes for specific purposes to promote
extensibility management.
A.1. Extensibility Framework
The extensibility framework of this standard is based on the premise that arbitrary network and protocol types can be
represented as unique values of +WS45 and +WS46, without any changes to this standard.
A DTE may take advantage of the provisions of this standard to determine the capabilities of an unknown DCE. One
possible exchange is:
Table A.1 - Example of DTE-DCE Negotiation
DTE Transmits:
DCE Transmits:
OK<CR><LF>
The DTE begins by initializing the DCE to issue
responses in the desired format.
ATE0V1<CR>
AT+W<CR>
OK<CR><LF>
The response from the DCE indicates whether or not
to continue the protocol. If the DCE responds with
ERROR, it is not compliant to this standard and the
DTE must use other means to assess its capabilities.
OK
AT+WS45=?<CR>
Here the DCE indicates that it can use Transparent,
Reliable Transparent, SLIP, and X.28 PAD DTE-Side
Stacks. If the DCE doesn’t support an appropriate
DTE-Side Stack, the DTE can stop the protocol and
declare the DCE incompatible.
(0,1,3,6)<CR><LF>OK<CR><LF>
AT+WS46=?<CR>
The DCE signals that it can operate on GSTN and
GSM Digital Cellular networks. Once, again, the DTE
can terminate the protocol if the DCE does not
support a suitable WDS type.
(1,12)<CR><LF>OK<CR><LF>
The DTE determines that it can map its protocol stack The DCE sets up to offer packet-based service over
onto SLIP, and that the desired endpoint address can GSM with a SLIP interface, and goes on-line in
be reached cost effectively over GSM. The DTE
response to the D command. No dial string is
issues the commands to set up the DCE, changing
needed, since the DTE is effectively connecting to a
+WS46 first since it might override the value of
dedicated DCE-based server which provides a SLIP
+WS45.
gateway.
AT+WS46=12;+WS45=3;D<CR>
CONNECT 9600<CR><LF>
The above exchange is insensitive to the number and type of DTE-Side and WDS-Side stacks implemented in the DCE,
and to the type of communication (e.g. circuit-switched, packet switched) desired by the DTE.
This standard is extensible with respect to future network types. Section 7.2 reserves a large portion of possible values
of +WS46 for allocation to future network types. Section 5.2.4.7 of this standard allows the DCE to change the set of
valid AT commands based upon the setting of +WS46 (the WDS-Side Stack). This lets the DCE “switch in” any extra
commands needed for new network types (the WDS-Specific AT Command Sets of Figure 6).
This standard is extensible with respect to future DTE interface protocols. Section 7.1 reserves a large portion of
possible values of +WS45 for allocation to future protocol types. Section 5.2.4.6 of this standard prohibits the DCE from
changing the set of valid AT commands based upon the setting of +WS45 (the DTE-Side Stack). However, the DTE-
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Side Stack may provide any control primitives needed via embedded escape sequences or control frames in On-Line
Data State.
This standard is extensible with respect to both WDS-Specific AT Command Sets, and the Common AT Command Set.
This standard uses only a small fraction of the possible ITU-T V.250 command names beginning with “+W”. Optional
extensions to the Common AT Command Set are topics of ongoing research and development.
Each of the four types of extensibility described above may be accomplished without changes to this standard. The
remainder of this section establishes guidelines for building on this standard.
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A.2. Command Set Extensions
A.2.1. Commands in Proposed Annexes
Command set extensions designed in compliance with the guidelines established in this standard may be submitted to
the committee for a letter ballot vote for approval as an Annex of this standard. The guidelines are:
(1)
A proposed annex which defines command set extensions shall contain either optional extensions to the
Common AT Command Set, or a proposed definition of a WDS-Specific AT Command Set, but not both.
(2)
A proposed annex which defines a WDS-Specific AT Command Set may designate individual new
commands or groups of new commands as either optional or mandatory for DCE supporting the
associated WDS type.
(3)
All command set extensions shall comply with the syntax and presentation format rules established in
this standard and ITU-T V.250 (e.g., all new commands must begin with +W).
(4)
The command prefix +WA is reserved for manufacturer-specific immediate action commands. Command
names using this prefix should not be included in Annexes.
(5)
The command prefix +WV is reserved for manufacturer-specific parameter commands. Command
names using this prefix should not be included in Annexes.
(6)
Command names +WS200 to +WS255, and command names consisting of +WS followed immediately
by any number greater than 255, are reserved for manufacturer-specific parameter commands using Sparameter-like syntax. Command names using this format should not be included in Annexes.
(7)
The following command names and prefixes are reserved for extensions to the Common AT Command
Set: +WS1 to +WS99 (entire name); +WC, +W!, +W%, +W-, +W., +W/, +W:, +W_ (any name with any of
these prefixes), and should be used only in Annexes which extend the Common AT Command Set.
(8)
A proposed annex may define new extended result codes, provided that the extended result codes
comply with ITU-T V.250 syntax and presentation rules, and each new result code begins with +W.
(9)
The result code prefix +W. (+W followed immediately by a period, ASCII 2E hex)is reserved for
manufacturer-specific result codes. These result codes should not be included in Annexes.
(10)
Each Annex which defines commands must define a mandatory action command to report a list of
names of other commands defined in that Annex and implemented by the DCE. The format of the
information text output by the command must be a list of quoted strings separated by commas. The list
may occupy multiple lines, but each line except the last must include a trailing comma; more than one
command may be reported per line. For example, if the defined command is +WFOO and the other
commands +WBAR, +WFIE, and +WS212 are implemented, the response to +WFOO might look like
this:
“+WS212”,”+WBAR”,
“+WFIE”
OK
The trailing OK is a standard TIA/EIA-602-A result code, and not part of the information text.
(11)
Each Annex must define a mandatory string to be reported by the +W command, to indicate that the
DCE implements some or all of the features defined in that Annex. The string must have the form
+W<text>. Refer to the description of +W for additional information.
A.2.2. Manufacturer-Specific Commands
This standard places no restrictions on syntax or operation of manufacturer-specific extensions. Such extensions are
not themselves compliant, but render the DCE non-compliant with this standard only if they prevent the DCE from
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satisfying specific provisions of this standard. Manufacturer-specific extensions may be incompatible with annexes of
this standard.
A.3. Recommended Annex Contents
Each annex should contain at least the following information:
Declaration of Scope
State whether this annex extends the Common AT Command Set, defines a WDSSpecific Command Set, or defines a DTE-Side Stack. Identify the relevant network type or
protocol.
Identify Resources Requested
A typical annex might request the allocation of +WS45 codes, +WS46 codes, or other
“name space” resources for the exclusive use of DCEs compliant with the Annex. Another
type of annex might refer to a resource already set aside by this standard (e.g., the
TDMA Cellular or GSM +WS46 codes, which have been set aside but for which no Annex
has been written).
Describe New DCE Features Using the Reference Models and Definitions of this Standard
Figure 1 - Figure 6 of this standard provide reference models for system-level, protocol,
and DCE architecture. Annexes which use the same terminology as this standard will
integrate easily with this standard and its annexes.
Describe New Commands Using the Formats of this Standard
This standard uses specific formats to describe different kinds of commands. Include at
least syntax, description, and implementation headings for action commands; add defined
values and recommended defaults headings for parameter commands. Other headings
might include abortability, side effects, and scope. Be sure to include the mandatory
Annex-specific command reporting command, and the mandatory identification string for
+W.
Provide Enough Detail to Promote Interworking
The detail in an annex should not be implementation detail, but it should provide
information that promotes interworking of DCE from manufacturers who comply. The
detailed portion can be as simple as a list of applicable standards and brief text explaining
how they relate to this standard; more and other detail may be provided as necessary.
Contributors should take care to distinguish informative material from normative material
in descriptions.
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Annex B, Miscellaneous Commands
B.1 Scope
This standard defines optional extensions to the protocol elements, procedures, and behaviors defined in the main body
of this standard. These extensions are based on the +WS and +WC command prefixes reserved by this standard for
standardized extensions.
This annex specifies optional general-purpose commands common to most wireless modems, in accordance with the
annex schedule set forth in Section A.4, Reserved Topics.
The commands defined in this annex extend the Common AT Command Set and have both unrestricted visibility and
global scope, in accordance with Section 5.4.1:
“All DCE parameters controlled by AT commands in the Common AT Command Set (ref. Figure 5) must have
unrestricted visibility and global scope, unless other visibility or scope is defined explicitly in an applicable
standard. Some of these parameters may have unstable or stable volatility. All AT commands defined in this
standard are, by definition, in the Common AT Command Set. Annexes of this standard may define optional
additions to the Common AT Command Set.”
In the case of parameter commands defined in this Annex, a single value of the parameter is shared by all implemented
WDS types, and the DTE must reprogram the parameter value as necessary when changing WDS types via the +WS46
command; the parameter command must be available for every supported value of +WS46. In the case of action
commands defined by this Annex, the action command must be available for every supported value of +WS46 and
always acts upon the currently selected WDS type.
B.2 Notes on Interrelated Commands
This annex defines two commands (+WS51 and +WS54) which control operation of the RLSD line when command &C1
is in effect. Each command establishes a condition which must be satisfied for assertion of RLSD given &C1. A DCE
manufacturer may establish additional conditions which control assertion of RLSD (for example, WDS-specific
parameter commands, hysteresis). Compliant operation is defined as follows:
1)
If either the signal strength threshold established by +WS51 or the channel quality threshold established by
+WS54 is not exceeded, RLSD will tend toward the negated state.
2)
If both the signal strength threshold established by +WS51 and the channel quality threshold established by
+WS54 are exceeded, RLSD will tend toward the asserted state.
“RLSD will tend toward the ___ state” means that in the absence of other influences (e.g. hysteresis, WSD-specific
factors) RLSD will have the specified state.
B.3 Miscellaneous Commands
B.3.1 Miscellaneous Parameter Commands
This section describes Miscellaneous Commands that conform to ITU-T V.250 rules for parameter commands.
NOTE: Some commands have been defined as “read-only” parameter commands instead of as action commands
displaying information text. The use of read-only parameter command syntax instead of action command syntax allows
the DCE to report a list of supported parameter values in response to the =? primitive, while conforming to ITU-T V.250
syntax and operational procedures.
B.3.1.1 Normalized Signal Strength
Syntax:
+WS50?
+WS50=?
Description:
Returns a value between 0 and 100, or 255, indicating a normalized signal strength for the currently
selected WDS. 0 indicates imperceptible signal strength, while 100 indicates "full-scale" or receiver saturation signal
strength. 255 indicates that the signal strength is unknown.
Implementation:
The specific interpretation of values is manufacturer-specific. If this command is implemented
at all, it is mandatory to implement *either* the value 255, or *at least* the values 0 and 100.
Parameter values in the range 101 to 254 may be used for manufacturer-specific extensions. DTE software should
interpret unrecognized values in the range 101 to 254 as equivalent to 255.
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+WS50=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default: 255
B.3.1.2 Carrier Detect Signal Strength Threshold
Syntax:
+WS51=n
+WS51?
+WS51=?
Description:
Sets the nominal signal strength indication that +WS50 must equal or exceed for the currently selected WDS to enable
assertion of the RLSD (carrier detect) line when command &C1 is in effect.
The value must be in the range 0 to 100, or 255, and must be one of the valid values for +WS50. A value of 255
indicates "don't care", and may enable manufacturer-specific / automatic behavior.
Implementation:
+WS51=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values. The manufacturer may implement arbitrary hysteresis to control de-assertion of RLSD (i.e. the signal strength at
which RLSD becomes de-asserted may be equal to, or arbitrarily lower than, the value of +WS51, depending on
implementation).
Parameter values in the range 101 to 254 may be used for manufacturer-specific extensions. DTE software should
interpret unrecognized values in the range 101 to 254 as equivalent to 255.
Refer to the description of +WS50 for additional information.
Recommended Default: 255
B.3.1.3 Normalized Battery Level
Syntax:
+WS52?
+WS52=?
Description:
Returns a value between 0 and 100, or 255, indicating a normalized DCE battery level. 0 indicates battery exhausted,
while 100 indicates "full-scale" or fully charged battery. 255 indicates that the battery level is unknown.
Implementation:
The specific interpretation of values is manufacturer-specific. In configurations using separate network adapter and
modem batteries, the value returned by +WS52? indicates the charge level of the modem battery.
If this command is implemented at all, it is mandatory to implement *either* the value 255, or *at least* the values 0 and
100.
Parameter values in the range 101 to 254 may be used for manufacturer-specific extensions. DTE software should
interpret unrecognized values in the range 101 to 254 as equivalent to 255.
+WS52=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default: 255
B.3.1.4 Normalized Channel Quality
Syntax:
+WS53?
+WS53=?
Description:
Returns a value between 0 and 100, or 255, indicating a normalized channel quality for the currently selected WDS. 0
indicates no contact, 1 indicates “minimum” or nearly unusable channel quality, and 100 indicates "full-scale" or nearly
ideal signal quality. 255 indicates that the channel quality is unknown.
Implementation:
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The specific interpretation of values is manufacturer-specific. If this command is implemented at all, it is mandatory to
implement *either* the value 255, or *at least* the values 0 and 100.
Parameter values in the range 101 to 254 may be used for manufacturer-specific extensions. DTE software should
interpret unrecognized values in the range 101 to 254 as equivalent to 255.
+WS53=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default: 255
B.3.1.5 Carrier Detect Channel Quality Threshold
Syntax:
+WS54=n
+WS54?
+WS54=?
Description:
Sets the nominal channel quality indication that +WS53 must equal or exceed for the currently
selected WDS to enable assertion of the RLSD (carrier detect) line when command &C1 is in effect.
The value must be in the range 0 to 100, or 255, and must be one of the valid values for +WS53. A value of 255
indicates "don't care", and may enable manufacturer-specific / automatic behavior. A value of 0 results in continuous
assertion of RLSD when &C1 is in effect.
Implementation:
+WS54=? behaves according to ITU-T V.250 rules for parameter commands, and must
enumerate only the supported values.
The manufacturer may implement arbitrary hysteresis to control de-assertion of RLSD (i.e. the signal quality at which
RLSD becomes de-asserted may be equal to, or arbitrarily lower than, the value of +WS54, depending on
implementation).
Parameter values in the range 101 to 254 may be used for manufacturer-specific extensions. DTE software should
interpret unrecognized values in the range 101 to 254 as equivalent to 255.
Refer to the description of +WS53 for additional information.
Recommended Default: 255
B.3.1.6 Registration Status
Syntax:
+WS56?
+WS56=?
Description:
Indicates the current DCE registration status for the selected WDS type from among not registered (0),
registered (1), registration denied (e.g. invalid user) (2), limited registration (e.g. guest access) (3), or automatic /
unknown (255).
Implementation:
The specific interpretation of values is manufacturer-specific. If this command is implemented
at all, it is mandatory to implement *either* the value 255, or *at least* the values 0 and 1.
Values in the range 4 to 199 are reserved for future standardization, while values in the range 200 to 254 are WDSspecific. DTE software should interpret any unknown value in the range 4 to 254 as equivalent to 255.
+WS56=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default: 255 (or 0)
B.3.1.7 Antenna Preference
Syntax:
+WS57=n
+WS57?
+WS57=?
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Description:
Selects or indicates the (antenna or other) port preference for the selected WDS type from among none (0), port A (1),
port B (2), or automatic / unknown (255).
Implementation:
The specific interpretation of values (including values other than 0 to 2 and 255) is manufacturer-specific. This
command typically controls antenna selection, either for switched antenna diversity or choice between internal / external
antennae, but for some WDS types the command might control other means of selecting among alternative “data paths”
between the DCE and the WDS infrastructure.
The value 255 typically enables diversity or some other automatic port selection mechanism. If this command is
implemented at all, it is mandatory to implement *either* the value 255, or *at least* the value 1.
Parameter values in the range 101 to 254 may be used for manufacturer-specific extensions. DTE software should
interpret unrecognized values in the range 101 to 254 as equivalent to 255.
+WS57=? behaves according to TIA-615 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default: 255 (or 1)
B.3.1.8 Idle Time-Out Value
Syntax:
+WS58=n
+WS58?
+WS58=?
Description:
Sets or indicates the idle time-out interval, after which the modem enters the manufacturer-specific
low-power state, as follows:
0
Immediate
1-60
n Seconds
61-120
(n-60) Minutes (e.g. 62 selects 2 minutes)
121-254 (n-120) Hours (e.g. 125 selects 5 hours)
255
Disable Idle Time-Out
When the idle time-out feature is enabled, the DCE continuously searches for the specified uninterrupted interval of
DTE-to-DCE and selected WDS-to-DCE inactivity. If such an interval is detected, the DCE suspends communication
and enters a low-power (or off) state. The value 0, if implemented, forces immediate entry into the low power state when
the idle time-out feature is enabled.
Implementation:
The interpretation of “suspends communication” is manufacturer-specific. The means for exiting the low-power state are
manufacturer-specific. The DCE may alter the states of some logical circuits when entering or exiting low-power mode.
If this command is implemented at all, *at least* value 255 must be implemented.
+WS58=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the valid range
of values.
Recommended Default: 255
B.3.2 Miscellaneous Action Commands
This section describes Miscellaneous Commands that conform to ITU-T V.250 rules for action commands.
B.3.2.1 Display System ID
Syntax:
+WCID
+WCID=?
Description:
Displays the "system ID" for the currently selected WDS. The system ID is an indication of network
operator or carrier identity, rather than of the selected communication technology or WDS type; it is typically derived
from information exchanged between the DCE and WDS.
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The command displays free-form information text (not a string constant) which must conform to ITU-T V.250 and the
format rules of this standard. Typical systems use numeric system IDs of 3-8 digits, but the application developer should
not assume that the response will be numeric.
One non-numeric information text format is predefined: UNKNOWN. Information text of UNKNOWN indicates that the
system ID is unknown, either because the concept of system ID does not exist for the currently selected WDS type, or
because the DCE is currently out-of-range.
Implementation:
The manufacturer may implement arbitrary time delays to control when +WCID changes between UNKNOWN and
some other value.
+WCID=? behaves according to ITU-T V.250 rules for action commands having no sub parameters.
B.3.2.2 Set Personal Identification Number
Syntax:
+WCPN="newPIN"[,"oldPIN"],
+WCPN=?
+WCPN="*"
Description:
Sets the personal identification number or password used to lock or unlock the DCE (see +WCLK).
newPIN is the desired PIN; if a PIN was set previously, the correct value of oldPIN (the current PIN) must also be
specified. In either case, the PIN is set to newPIN. To remove the PIN completely, newPIN should be the empty string
(mandatory format "").
The literal syntax +WCPN="*" places the DCE into a new operating state, NEWPIN ENTRY STATE. In this state, the
DCE issues the intermediate result code +WNEWPIN: and then accepts characters up to a command line
termination character as equivalent to newPIN. The DCE then always (regardless of whether a PIN was previously set)
advances to a second new state, PIN ENTRY STATE. In this state, the DCE issues the intermediate result code
+WPIN: and then accepts characters up to a command line termination character as equivalent to oldPIN.
The DCE then executes the +WCPN command using the specified values of newPIN and oldPIN, and returns to
command state.
In both NEWPIN ENTRY STATE and PIN ENTRY STATE, the values of DCE parameters E and V are overridden to
E0V1 (no echo, verbose results); these parameters revert to their previous values before issuing a final result code and
before processing additional commands. All other command line editing parameters, including the command line
termination character, command line echo, backspace character, etc. are honored during data entry in either new state.
PIN values entered in either of these states are not enclosed in quotes.
Implementation:
+WCPN=? behaves according to ITU-T V.250 rules for action commands.
If this command is supported, the DCE must accept all forms of the command described in this Annex, including
+WCPN="*".
The DCE is permitted, but not required, to ignore any commands which follow +WCPN="*" on the same line.
Some devices may use numeric PINs, while others may allow arbitrary text PINs; in either case, a PIN on the command
line must be enclosed in double quotes (according to the rules for string parameters).
B.3.2.3 Lock / Unlock DCE
Syntax:
+WCLK=n[,"currentPIN"]
+WCLK=?
+WCLK=n,"*"
Description:
Enables (n=0) or disables (n=1) use of the DCE. If the device supports a PIN, the PIN must be
included with the command as currentPIN. See also +WCPN.
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The literal syntax +WCLK=0,"*" or +WCLK=1,"*" places the DCE into a new operating state, PIN ENTRY STATE. In
this state, the DCE issues the intermediate result code
+WPIN: and then accepts characters up to a command
line termination character as equivalent to currentPIN. The DCE then executes the +WCLK command using the
specified value of currentPIN, and returns to command state.
Refer to the description of +WCPN for additional information on PIN ENTRY STATE.
Implementation:
The exact interpretations of enabling and disabling are manufacturer-specific, but the DCE must continue to accept the
+WCLK command regardless of whether the DCE is locked.
+WCLK=? behaves according to ITU-T V.250 rules for action commands.
Refer to the description of +WCPN for additional information.
B.3.2.4 Display Battery Charging Status
Syntax:
+WCHG
+WCHG=?
Description:
Displays either 0 (battery not charging) or 1 (battery charging) following ITU-T V.250 rules for information text.
Implementation:
+WCHG=? behaves according to ITU-T V.250 rules for action commands having no sub parameters.
B.3.2.5 Display Data Link Address
Syntax:
+WCDA
+WCDA=?
Description:
Displays the DCE data link address for the selected WDS type as free-form information text (not a string constant),
following ITU-T V.250 formatting rules.
One non-numeric information text format is predefined: UNKNOWN. Information text of UNKNOWN indicates that the
data link address is unknown, either because the concept of data link address does not exist for the currently selected
WDS type, or because the DCE does not currently have a data link address assigned.
Implementation:
+WCDA=? behaves according to ITU-T V.250 rules for action commands having no sub parameters.
The format and interpretation of the displayed address is WDS-specific; some WDS may display more than one address
in response to this command; the display may occupy more than one line. It is strongly recommended that each WDSspecific Annex define a standard format and interpretation.
B.3.2.6 Display Supported Annex B Commands
Syntax:
+WCXF
+WCXF=?
Description:
This command allows the DCE to report back to the DTE which of the commands defined in this Annex it has
implemented.
When the DTE invokes this action (via +WCXF) the DCE must output the names of implemented Miscellaneous
Commands. Each name will be delimited by double quotes, the quoted strings being separated by commas. The list
includes the names of all supported Annex F commands, with the exception of +WCXF which is not reported. The
output may occupy multiple lines, following ITU-T V.250 rules for information text.
For example, a DCE operating supporting only the +WS50 and +WS51 commands (besides +WCXF) would respond to
+WCXF with:
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“+WS50”,”+WS51”<end-of-info-text delimiter, e.g. CR/LF>
OK<delimiter>
Implementation:
+WCXF=? behaves according to ITU-T V.250 rules for action commands having no sub parameters.
Implementation of this command is mandatory if any commands defined in this Annex are implemented.
B.4 Additions to +W Command
This standard defines the mandatory +W command which reports a list of supported Standards and Annexes. DCE
which support any commands defined in this Annex must report the string “+WCXF” to the left of the string “101”, and
to the right of the first string associated with any other standard.
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Annex C - Command Extensions for Analog Cellular Data Modems
C.1 Scope
This annex specifies optional vendor-independent but network-specific commands for DCE used to transmit data via the
AMPS (Advanced Mobile Phone System) analog cellular phone system. The AMPS system is specified by the following
normative references:
EIA/TIA-553, September 1989, Mobile Station -- Land Station Compatibility Specification
EIA/IS-19-B, May 1988, Recommended Minimum Standards for 800-MHz Cellular Subscriber Units
EIA/IS-20-A, May 1988, Recommended Minimum Standards for 800-MHz Cellular Land Stations
The commands in this annex would typically be implemented in a 'V series' modem, such as V.22bis, or V.32bis
modified to communicate directly with an analog cellular phone. The wireless analog cellular phone would replace the
wired GSTN subscriber loop connection. Commands specific to non-AMPS cellular phone systems such as CDPD,
TDMA, and CDMA are not covered in this annex.
C.2 Invocation
Analog Cellular Data configuration is normally invoked by issuing the +WS46=7 command. (See § 5.2.4.7, § 7.2) The
+WS46=7 command will not be necessary if the DCE power-up mode sets +WS46 to 7, and +WS46 had not since
power-up been set to some other value.
C.3 Configuration
Regardless of method used to enter the Analog Cellular Data mode, the DCE must be able to send and receive control
signals to and from the cellular phone control processor. This control path is necessary for successful completion of the
majority of the commands in this annex. Such a bus allows the DCE to interrogate and control the phone, taking
advantage of its additional analog cellular features. An example would be the ability to monitor received cellular RF
signal strength. As such, setting +WS46=7 only makes sense when such a bus exists and therefore requires it. In this
annex, this bus will be referred to as the cell-bus. Note that the cellular phone control processor and the modem control
processor may be the same. In this case the cell-bus is a virtual data path within the control processor. Further, this
standard places no limits on the physical connection between or locations of the modem and cellular control processors.
By setting +WS46=7, the cell-bus is automatically enabled. Setting +WS46 to any value other than 7 disables the cellbus. Figure C.1 illustrates the general relationship between the cell-bus and the rest of the major components. Figure
C.1 is not meant to be totally authoritarian, that is, any other vendor chosen alternate configuration that performs the
same functions would be acceptable.
Generally, there is associated with the cell-bus an analog path for transmitting and receiving the audio signals directly to
and from the cellular phone. As such, setting +WS46=7 also routes audio signals through an analog portion of the cellbus.
The ability of the cell-bus to transfer control and status information and audio signals between the DCE and the cellular
phone is all that is specified concerning the cell-bus. Electrical parameters and digital information format are totally
vendor specific.
Antenna
DTE
DCE
EIA-232
Cell-Bus
Cellular
Phone
Figure C.1 Analog Cellular Data General Remote Configuration.
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C.4 Analog Cellular Result Codes
For command entry errors such as command name or parameter errors the standard ERROR <CR><LF> error
message will be used. To indicate error conditions pertinent to analog cellular data specific functionality, +WERROR:
n<CR><LF> will be used, where n is an error code. Table C-1 below specifies values for n, and the associated
condition causing the error.
Table C.1 - Error Codes and Meanings
n
1
2
3
Condition
DCE cannot communicate with cellular phone. Reason unknown.
DCE cannot communicate with cellular phone because the cell-bus is
disconnected.
DCE cannot communicate with cellular phone because phone is powered down.
C.5 Analog Cellular Data Mode Commands
Section C.5 contains descriptions of each of the commands that make up this annex. Note that the only command that
is mandatory is the Data over Analog Cellular Commands Query Command, +WDAC. All other commands are optional.
C.5.1 Data over Analog Cellular Commands Query
Action Syntax
+WDAC
+WDAC=?
(display valid commands)
(test command)
Description
This command allows the DCE to report back to the DTE which of the commands of the Analog Cellular Data Modems
annex it has implemented.
When the DTE invokes this action (via +WDAC) the DCE must output the names of implemented Data over Analog
Cellular commands. Each name will be delimited by double quotes, the quoted strings being separated by commas.
The names will be a subset of the list of valid analog cellular data command names, excluding "+WDAC". These would
be the following, in the given order:*
+WCTO,+WECR,+WRLK, +WFON,
+WBAL,+WDIR, +WPBA, +WPTH
For example, assume the DCE supported only the +WCTO and +WECR analog cellular data commands. The output
would be:
"+WCTO","+WECR"<CR><LF>
OK<CR><LF>
The DCE may also present the sub-strings in a multi-line format as follows:
"+WCTO",<CR><LF>
"+WECR"<CR><LF>
OK<CR><LF>
Note that a trailing comma is used to indicate continuation onto another line.
The DTE responds to the action test format (via +WDAC=?) with OK<CR><LF>.
Since +WDAC is an action command, it will return an ERROR<CR><LF> result code if the DTE attempts to set it to a
value (via +WDAC=<value>), or to read a value (via +WDAC?).
Defined Values
+WDAC is an action command and therefore has no values.
* This list subject to change if commands are added to or deleted from this annex.
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Recommended Default Setting
+WDAC is an action command and therefore has no default setting.
Implementation
Implementation of this command is mandatory.
C.5.2 Call Session Time Limit
Parameter Syntax
+WSTL=<value>
+WSTL?
+WSTL=?
(set time-out)
(display current time-out)
(display valid time-outs)
Description
Allows the user to specify a call Session Time Limit threshold. Any call that has logged more than this threshold is
automatically terminated. The threshold is specified in terms of 10 second segments. For instance, if +WSTL was set
to 8, a call time limit of 80 seconds would be configured. The timer begins at the instant after dialing.
The DCE must output the current setting of the +WSTL parameter when the DTE queries for this parameter (via
+WSTL?).
The DCE sets the maximum call duration in minutes when the DTE sets this parameter to a valid value (via +WSTL=
<value>).
The DCE must output an OK<CR><LF> result code when the DCE tests for this command (via +WSTL=?).
Defined Values
0
1<=+WSTL<=255
Disables the automatic time-out feature.
Sets the call duration time-out to the specified value.
Recommended Default Setting
The recommended default setting of +WSTL is 0, which defaults it to disabled.
Implementation
Implementation of this command is optional.
C.5.3 Enable Cellular Result Codes
Parameter Syntax
+WECR=<value>
+WECR?
+WECR=?
(enable/disable cellular result codes)
(display current cellular result codes setting)
(display valid cellular result codes settings)
Description
The analog cellular system may present the DCE with signaling beyond what is common in the GSTN. For instance,
when there is no channel available for a requested link, the cellular system responds with a 'REORDER' message. It
may be desired to relay this information from the cellular phone all the way back to the DTE. Some user applications
designed to interface with standard modems are expecting standard result codes. Defaulting to non-cellular result
codes permits the DCE to interface with these existing communications packages.
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Implementation of the Enable Cellular Responses command affords the more informative cellular specific result codes
to analog cellular data compatible applications. Table C.2 lists the extended result codes, and the GSTN result codes
that will be used as substitutes when the extended result codes are disabled (via +WECR=0)
Table C.2 - Cellular Responses and GSTN Responses
Extended
Result Code
+WLOCKED
+WINTERCEPT
+WREORDER
+WDROPPED CALL
+WCALL TIMEOUT
+WROAM LOCKOUT
+WNO SERVICE
+WLOW RSSI
GSTN
Result Code
NO DIALTONE
BUSY
BUSY
NO CARRIER
NO CARRIER
NO DIALTONE
NO DIALTONE
NO DIALTONE
The DCE must output the current setting of the +WECR parameter when the DTE queries for this parameter (via
+WECR?).
The DCE enables or disables the cellular result codes when the DTE sets this parameter to a valid value (via +WECR=
<value>).
The DCE must output the list of valid +WECR settings when the DCE tests for this command (via +WECR=?).
Defined Values
0
1
Use GSTN result codes.
Use Cellular result codes.
Recommended Default Setting
The default setting is 0, to use GSTN result codes.
Implementation
Implementation of this command is optional. Regardless of whether the +WECR command is implemented, the
standard GSTN result codes are mandatory.
C.5.4 Roam Lockout
Parameter Syntax
+WRLK=<value>
+WRLK?
+WRLK=?
(enable/disable roam lockout)
(display current roam lockout setting)
(display valid roam lockout settings)
Description
Enabling the Roam Lockout feature disallows answering or originating calls when the cellular transceiver is in the roam
mode.
The DCE must output the current setting of the +WRLK parameter when the DTE queries for this parameter (via
+WRLK?). The DCE must output a list of valid +WRLK settings when the DTE tests for this parameter (via +WRLK=?).
Defined Values
0
1
Disables Roam Lockout. Allows originating and answering calls in Roam mode.
Allows originating and answering calls in non-Roam mode only.
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Recommended Default Setting
The default setting is 0, disabling Roam Lockout.
Implementation
Implementation of this command is optional.
C.5.5 Phone Specification
Parameter Syntax
+WFON=<"string">
+WFON?
+WFON=?
(set phone ID)
(display current phone ID)
(display valid phone Ids)
Description
This command is used to specify to the DCE the type of cellular phone that it is connected to via its cellular specific
connection. The parameter is set to a string type setting. For example, +WFON= "XYZ52"<CR>. The parameter is
limited to 16 characters maximum in length. Vendors are recommended to keep the parameter strings much shorter
than that.
When the DTE sets this parameter to a valid string (via +WFON= <"string">) the DCE may use this information in any
way the manufacturer sees fit. For instance, transmit levels may be adjusted appropriately, or keypad emulation may
be tailored to the specified phone.
For devices that integrate a modem and cellular phone hard-wired, +WFON will be set to the sting "INTERNAL".
The DCE must output the current string setting of the +WFON parameter when the DTE queries for this parameter (via
+WFON?).
The DCE must output a list of valid +WFON string settings when the DTE tests for this parameter (via +WFON=?).
The DCE will return an ERROR<CR><LF> result code if the DCE determines that it is unable to support the requested
phone type.
Defined String Values
Defined string values are vendor specific.
Recommended Default Setting
The default setting is vendor specific.
Implementation
Implementation of this command is optional.
C.5.6 Bias Modem Audio Gain
Parameter Syntax
+WBAG=<value>
+WBAG?
+WBAG=?
(set gain level)
(display current gain level)
(display valid gain levels)
Description
The +WBAG command is used to Bias the DCE Audio output Gain. (Please note that this has nothing to do with the
wireless transceiver RF output power level.) Since audio interface impedance varies from vendor to vendor, dBm units
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are inappropriate. The command will therefore be used to bias on a relative basis in 1 dB steps from the vendor
suggested (default) audio output level. For example, if the DTE sets the value of +WBAG to 2, (via +WBAG=2) the
modem audio output level to the phone would be 2 dB above the vendor suggested level.
In on-line command mode, a vendor suggested level is determined after the modulation technique has been selected
during data mode. This becomes the current vendor suggested level. The current allowable biasing range is now
based on the current vendor suggested level, and may therefore differ from the off-line range. If the off-line setting is
outside the current valid bias range, the actual biasing is limited to the current range, but +WBAG is not changed.
In either off-line or on-line command mode, the DTE may set this parameter to a valid value via +WBAG= <value>. An
ERROR <CR><LF> result code is returned if the command is not supported in the current mode, or if the +WBAG
value specified by the DTE is outside the current valid range. If this command is implemented in the current mode, the
DCE must output a list of valid +WBAG settings when the DTE tests for this parameter (via +WBAG=?).
The DCE must output the current string setting of the +WBAG parameter when the DTE queries for this parameter (via
+WBAG?).
If the +WBAG parameter is modified during on-line command mode, that setting carries over to the following off-line
command mode.
Defined Values
The valid range of decimal settings is vendor specific and may be both positive and negative.
Recommended Default Setting
The default setting is 0.
Implementation
The vendor may opt to implement +WBAG as:
1) Off-line command mode only,
2) Both off-line and on-line modes
3) Not at all.
C.5.7 Keypad Emulation
Action Syntax
+WKPD
+WKPD <"string">
+WKPD=?
(enter keypad emulation mode)
(interpret "string" as keypad input)
(test command)
Description
The keypad emulation command allows the DTE to drive the cellular phone as if the DTE had access to the handset
KeyPaD. This is initiated by the DTE sending to the DCE an ASCII character to represent each keystroke desired. The
DCE then sends the appropriate command(s) via the cell-bus to the cellular phone to carry out the functions requested
by the DTE.
The DTE command string may be supplied as an argument to the +WKPD command (via +WKPD <"string">). If the
+WKPD command is entered without an argument (via +WKPD <CR>) the commands are entered interactively. A
second <CR> terminates the interactive session.
Table C-3 defines the standardized codes. Character strings delimited by single quotes ("'"ASCII 27H) are interpreted
as alpha entries. For instance while CS is interpreted as the command pair <Clear Send>, 'CS' is interpreted as the
character pair "CS".
The DCE may also (vendor option) emulate the handset LCD/LED display by sending back to the DTE those display
responses that would be shown on the cellular phone's display panel in response to command input. Each phone
display response is followed by the line terminator characters stored in the S3 and S4 registers, typically <CR> and
<LF>. If the vendor supplies the display emulation option, it defaults to being on. The display emulation is disabled by
enclosing the command(s) within brackets ([] ASCII 5BH and 5DH).
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Command entry and response may be done in an interactive mode. The interactive mode is initiated by typing
+WKPD<CR> without an argument. The interactive session is terminated by entering another <CR>.
A sample interactive session is shown below. Note that since the digits of the phone number are enclosed in brackets
there is no LCD emulation for this portion of the command. Had the brackets not been used, each digit of the phone
number would be echoed back twice: once by the DCE, and once by the LCD emulator. The S (Send) character, being
non-enclosed, displays back the IN USE<CR><LF> message. (Display Emulation responses are vendor defined.)
DTE Entry
AT+WKPD<CR>
[5551212]S
<CR>
DCE Response
IN USE<CR><LF>
OK<CR><LF>
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Table C-3 Keypad Emulation Codes
Button
Char
#
P
Reserved
*
Reserved
<
>
0 to 9
ALPHA
A
B
CLR
VOLUME DN
END
FCN
Reserved
LOCK
MENU
PWR
MUTE
RCL
SEND
STO
VOLUME UP
v
AUX
^
#
%
& to )
*
+ to /
<
>
0 to 9
@
A
B
C
D
E
F
G to K
L
M
P
Q
R
S
T
U
V
X
^
ASCII(HEX)
A/a
23
25
26 to 29
2A
2B to 2F
3C
3E
30 to 39
40
41/61
42/62
43/63
44/64
45/65
46/66
47/67 to 4B/6B
4C/6C
4D/6D
50/70
51/71
52/72
53/73
54/74
55/75
56/76
58/78
5E
Comment
Pound Sign (Number Sign)
percent
Reserved
Star Key
Reserved
Left Arrow
Right Arrow
Numeric digits
alpha
A Channel
B Channel
Clear
Down
End
Function
Reserved
Lock
Menu
Power (Turn off only)
Quiet
Recall
Send
sTore
Up
Down Arrow (use 'V' or 'v' char)
auXilary
Up Arrow
An alternative form of the command allows a command string to be specified on the same line as the command
invocation as:
AT+WKPD "[5551212]S"<CR>
The DTE would then receive the IN USE message from the cellular phone and <CR>OK<CR><LF> result codes from
the DTE.
The DCE must output an OK<CR><LF> result code when the DTE tests for this action (via +WKPD=?).
The DCE must output an ERROR<CR><LF> result code when the DTE attempts to set +WKPD to a value (via
+WKPD= <value>), or if the DTE attempts to query +WKPD (via +WKPD?)
Defined Values
+WKPD is an action command. It therefore has no value.
Recommended Default Setting
+WKPD is an action command. It therefore has no default setting.
Implementation
Implementation of this command is optional.
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C.5.8 Phone Number Directory Selection
Parameter Syntax
+WDIR=<value>
+WDIR?
+WDIR=?
(set phone directory setting)
(display current phone directory setting )
(display valid phone directory settings)
Description
The DIRectory selection command allows the DTE to specify whether the DCE or cellular phone directory is selected for
storing, viewing, and using phone numbers (via +WDIR= <value>). If the modem uses a number from the cellular
phone directory to dial (via ATDS), the modem will still be considered as the calling agent. In other words, a data call
would ensue, not a voice call.
The DCE must output the current setting of the +WDIR parameter when the DTE queries for this parameter (via
+WDIR?).
The DCE must output a list of valid +WDIR settings when the DTE tests for this parameter (via +WDIR=?).
If the phone's directory is selected, the DCE will return an ERROR<CR><LF> result code if it is currently unable to
query the phone due to any configuration problem.
Defined Values
0
The DCE will use its own phone number directory when dialing, viewing, and storing phone numbers.
1
The DCE will use the cellular phone's phone number directory when dialing, viewing, and storing phone
numbers.
Recommended Default Setting
The recommended default setting will be 0, to use the DCE's internal phone number directory.
Implementation
Implementation of this command is optional.
C.5.9 Phone Battery Query
Parameter Syntax
+WPBA?
+WPBA=?
(display current phone battery charge level)
(display valid phone battery charge levels)
Description
This parameter is read-only. The DCE must output remaining Phone BAttery charge level indication when the DTE
queries for this parameter (via +WPBA?). The output would range from 0 to 100 with 0 representing 'no charge' and
100 representing a full charge. Values from 101 to 254 are manufacturer-specific return values. The value 255 means
‘unknown’.
The DCE must return to a list of valid DCE battery charge levels when the DTE tests for this parameter (via +WPBA=?).
+WPBA being read-only, the DCE must return to the DTE an ERROR<CR><LF> result code when the DTE attempts to
set this parameter (via +WPBA=<value>).
Defined Values
The read-only return parameter value ranges from decimal 0 for no charge to decimal 100 for full charge. Values from
101 to 254 are manufacturer-specific return values. The value 255 means ‘unknown’.
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Recommended Default Setting
+WPBA is a read-only parameter used for monitoring the phone battery charge level. It therefore has no default
setting.
Implementation
Implementation of this command is optional.
C.5.10 Call Path
Parameter Syntax
+WPTH=<value>
+WPTH?
+WPTH=?
(set call path)
(display current call path)
(display valid call paths)
Description
The call PaTH command routes incoming and outgoing calls to/from the modem and voice unit.
Setting +WPTH to 0 (via +WPTH=0) routes incoming calls to the voice handset. Outgoing calls are also considered
voice handset calls regardless of whether the dial string was entered via handset or ATD command.
Setting +WPTH to 1 (via +WPTH=1) routes incoming calls to the modem. Outgoing calls are also considered modem
calls regardless of whether the dial string was entered via handset or ATD command
The DCE must return to a list of valid DCE battery charge levels when the DTE tests for this parameter (via +WPTH=?).
Defined Values
0
1
Route calls to/from voice handset.
Route calls to/from modem.
Recommended Default Setting
The default setting is manufacturer defined.
Implementation
Implementation of this command is optional.
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Annex D - Command Extensions for PAD Control in Packet Networks
D.1
Scope
This annex specifies optional commands that control a packet assembler/disassembler in wireless-capable Data
Communications Equipment (DCE), for communication with a wide-area network (WAN).
D.2. PAD Control Parameter Commands
This section describes PAD Control Commands that conform to ITU-T V.250 rules for parameter commands.
D.2.1. Time-Independent Escape Sequence Enable
Parameter Syntax:
+WS60=n
+WS60?
+WS60=?
(set TIES)
(display current TIES setting)
(display valid TIES settings)
Description:
Enables the Time-Independent Escape Sequence (TIES) as an additional mechanism for return to the online command
state (other than any mechanism enabled by the &D command).
+WS60=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values
Defined values:
0
1
TIES disabled.
TIES enabled.
Recommended Default Setting
The default setting is 0, disabling TIES
Implementation
Implementation of this command is optional
D.2.2. Disconnect Procedure
Parameter Syntax:
+WS61=n
+WS61?
+WS61=?
(select disconnect procedure)
(display current disconnect procedure setting)
(display valid disconnect procedure settings)
Description:
Determines the procedure used by the DCE in disconnecting (transitioning from the online state to the offline command
state).
Defined values:
0
Terminate packet, transmit buffered WAN-bound data packets before disconnect.
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1
2
3
Do not terminate packet currently being constructed, but do transmit any buffered WAN-bound data packets
before disconnect.
Flush data and disconnect.
Flush data, deregister, and disconnect (same as 2 if the selected WAN does not support deregistration).
Note that the disconnect procedure as determined by +WS61 may not be followed in its entirety if the DCE is out of
communication with the WAN.
+WS61=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default Setting
The default setting is 0.
Implementation
Implementation of this command is optional
D.2.3. Local Online Echo Enable
Parameter Syntax:
+WS62=n
+WS62?
+WS62=?
(set Local Online Echo)
(display current setting)
(display valid settings)
Description
Enables or disables the DCE’s capability to echo data from the DTE in the online data state. If Local Online Echo is
enabled, the DCE will echo each character received from the DTE during the online data state. If both Local Editing and
Local Online Echo are enabled, upon receipt of the backspace character (determined by +WS73), the DCE will echo the
following character sequence to the DTE:
backspace character
space (2016)
backspace character
+WS62=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Defined values
0
1
Local Online Echo disabled
Local Online Echo enabled
Recommended Default: 0
Implementation
Implementation of this command is optional.
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D.2.4. Forwarding Character Feature Mask
Parameter Syntax:
+WS63=n
+WS63?
+WS63=?
(set Forwarding Character Feature Mask)
(display current Forwarding Character Feature Mask)
(display valid Forwarding Character Feature Masks)
Description
This register contains a bit mask that controls the PAD’s use of the primary and secondary forwarding characters. The
bit assignments are as follows:
Bit 0 - If set, the PAD will terminate WAN-bound packets upon receipt of the primary forwarding character from the DTE.
Bit 1 - If set, the PAD will include the primary forwarding character in WAN-bound data (i.e., will not filter-out the primary
forwarding character).
Bit 2 - If set, the PAD will terminate WAN-bound packets upon receipt of the secondary forwarding character from the
DTE.
Bit 3 - If set, the PAD will include the secondary forwarding character in WAN-bound data (i.e., will not filter-out the
secondary forwarding character).
Bit 4 - Unused
Bit 5 - Unused
Bit 6 - Unused
Bit 7 - Unused
+WS63=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default:
3 (bits 0 and 1 set) - if +WS64 is implemented
15 (bits 0, 1, 2, and 3 set) if both +WS64 and +WS65 are implemented.
12 (bits 2 and 3 set) if only +WS65 is implemented.
Implementation:
If either +WS64 or +WS65 are implemented, +WS63 must be implemented. If only +WS64 is implemented and +WS65
is not implemented, the DCE will use bits 0 and 1 of +WS63 and ignore bits 2 and 3 of +WS63. If only +WS65 is
implemented and +WS64 is not implemented, the DCE will ignore bits 0 and 1 of +WS63 and use bits 2 and 3 of
+WS63.
D.2.5. PAD Primary Forwarding Character
Parameter Syntax:
+WS64=n
+WS64
+WS64=?
Description
Receipt of this character (if enabled in the Forwarding Character Feature Mask) will cause the DCE to terminate the
packet, and to begin transmission of the packet to the WAN. Defined values are: 0-255
+WS64=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default
13
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Implementation
If +WS64 is implemented, +WS63 must be implemented
D.2.6. PAD Secondary Forwarding Character
Parameter Syntax
+WS65=n
+WS65
+WS65=?
(set PAD Secondary Forwarding Character)
(display current PAD Secondary Forwarding Character)
(display valid PAD Secondary Forwarding Characters)
Description
Receipt of this character (if enabled in the Forwarding Character Feature Mask) will cause the DCE to terminate the
packet, and to begin transmission of the packet to the WAN. Defined values are: 0-255
+WS65=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default
13
Implementation
If +WS65 is implemented, +WS63 must be implemented.
D.2.7. Packet Termination Upon Entering Online Command State
Parameter Syntax
+WS66=n
+WS66?
+WS66=?
(set Packet Termination upon entering Online Command State)
( display current value of Packet Termination variable)
( display valid values for Packet Termination variable)
Description
Determines whether or not the PAD will terminate an unterminated WAN-bound packet if the DCE enters the Online
Command State. Defined values are:
0
1
Packet will not be terminated.
Packet will be terminated.
If 0 is chosen, all buffered characters in the unterminated WAN-bound packet will be discarded when the DCE
enters the Online Command State.
The disconnect procedure determined by +WS61 may override the behavior determined by +WS66.
+WS66=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default
1
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Implementation
Implementation of this command is optional.
D.2.8. No Data Disconnect
Parameter Syntax
+WS67=n
+WS67?
+WS67=?
(set No Data Disconnect)
(display current value of No Data Disconnect)
(display valid No Data Disconnect values)
Description
Number of minutes of continuous loss of WAN contact, after which the DCE transitions to the offline command state if
there is no buffered WAN-bound data. Defined values are:
0
1 - 255
“No Data Disconnect” disabled.
Delay in minutes for “No Data Disconnect”.
If the DCE is unable to communicate with the WAN, it may be impossible for the DCE to perform all of the actions
defined by +WS61 when performing a “No Data Disconnect”.
+WS67=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default
0
Implementation
Implementation of this command is optional.
D.2.9. Data Disconnect
Parameter Syntax
+WS68=n
+WS68?
+WS68=?
(set Data Disconnect)
(display current Data Disconnect value)
(display valid Data Disconnect values)
Description
Number of minutes of continuous loss of WAN contact, after which the DCE transitions to the offline command state
even if there is buffered WAN-bound data. Defined values are:
0
1 - 255
“Data Disconnect” disabled.
Delay in minutes for “Data Disconnect”.
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If the DCE is unable to communicate with the WAN, it may be impossible for the DCE to perform all of the actions
defined by +WS61 when performing a “Data Disconnect”. Specifically, all WAN-bound data will be flushed when
performing a “Data Disconnect”.
+WS68=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default
0
Implementation
Implementation of this command is optional.
D.2.10. PAD Break Handling
Parameter Syntax
+WS69=n
+WS69=?
+WS69=?
(set PAD Break Handling value)
(display current PAD Break Handling value)
(display valid PAD Break Handling values)
Description
Determines the action to be taken by the DCE upon receipt of a break from the DTE (while in the Online data state).
Defined values are:
0 - Take no action
1 - Return to the Online Command state
2 - Disconnect, and return to the offline command state
If +WS69 is set to 2, the DCE will follow the behavior determined by +WS61 (Disconnect Procedure).
+WS69=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default
0
Implementation
Implementation of this command is optional.
D.2.11. PAD Inter-Character Timer
Parameter Syntax
+WS70=n
+WS70?
+WS70=?
(Set PAD Inter-Character Timer)
(Display current PAD Inter-Character Timer)
(Display valid PAD Inter-Character Timer values)
Description
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Delay time after which the DCE will terminate a packet (and forward it to the WAN) if no input is received from the DTE
and no other packet termination conditions have been met. Supported values are:
0
1 - 255
Inter-Character Timer disabled
Delay in tenths of seconds.
If no characters are received from the DTE in the time specified, the DCE will terminate the packet and forward it to the
WAN.
+WS70=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default
50
Implementation
Implementation of this command is optional.
D.2.12. PAD Inter-Line Timer
Parameter Syntax
+WS71=n
+WS71?
+WS71=?
(Set PAD Inter-Line Timer)
(Display current PAD Inter-Line Timer values)
(Display valid PAD Inter-Line Timer values)
Description
Delay time after which the DCE will terminate a packet (and forward it to the WAN) if a carriage return (ASCII 13) is not
received from the DTE, and no other packet termination conditions have been met. Supported values are:
0
1 - 255
Inter-Character Timer disabled
Delay in tenths of seconds.
If a carriage return is not received from the DTE in the time specified, the DCE will terminate the packet and forward it to
the WAN.
+WS70=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default
0
Implementation
Implementation of this command is optional.
D.2.13. PAD Input Buffer Editing Enable
Parameter Syntax
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+WS72=n
+WS72?
+WS72=?
(set PAD Input Buffer Editing Enable)
(display current value of PAD Buffer Editing Enable)
(display valid PAD Buffer Editing Enable values)
Description
Enables or disables the DCE’s capability to perform local editing of WAN-bound data. Values are:
0
1
Local editing disabled.
Local editing enabled
If local editing is enabled, the DCE will remove one character from the PAD’s input buffer upon receipt of the character
specified by +WS73. If both local editing and local echo are enabled, upon receipt of the backspace character, the DCE
will echo the following character sequence to the DTE:
backspace character
space (2016)
backspace character
If the PAD’s input buffer is empty (or contains only backspace characters), when a backspace character is received, the
character will be appended to the contents of the input buffer, regardless of whether or not local editing is enabled. (i.e.,
the PAD will not drop the backspace under these conditions even if local editing is enabled.)
If +WS72 is implemented, +WS73 must be implemented.
+WS72=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default
0
Implementation
Implementation of this command is optional.
D.2.14. PAD Input Buffer Backspace Character
Parameter Syntax
+WS73=n
+WS73?
+WS73=?
(set PAD Input Buffer Backspace Character)
(display current PAD Input Backspace Character)
(display valid PAD Input Backspace Characters)
Description
Selects the character to be used by the DCE as “backspace” if local editing is enabled (via +WS72).
If local editing is enabled, the DCE will remove one character from the PAD’s input buffer upon receipt of the character
specified by +WS73. If both local editing and local echo are enabled, upon receipt of the backspace character, the DCE
will echo the following character sequence to the DTE:
backspace character
space (2016)
backspace character
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If +WS73 is implemented, +WS72 must be implemented.
+WS73=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the supported
values.
Recommended Default
8
Implementation
Implementation of this command is optional.
D.2.15. PAD Maximum Packet Length
Parameter Syntax
+WS74=n
+WS74?
+WS74=?
(set PAD Maximum Packet Length)
(display PAD Maximum Packet Length)
(display valid PAD Maximum Packet Lengths)
Description
Sets the maximum length of packet to be generated by the DCE. Upon receipt of +WS74 characters from the DTE, the
DCE will terminate the packet, even if other packet termination conditions have not yet been met.
The range of values is manufacturer-specific, with the exception that 0 is not an allowable value.
+WS74=? behaves according to ITU-T V.250 rules for parameter commands, and must enumerate only the valid range
of values.
Recommended Default
255
Implementation
Implementation of this command is optional.
D.2.16. Display Memory Usage
Action Syntax
+WCMEM
+WCMEM=?
Description
Displays the usage of memory by the DCE’s PAD.
The command displays free-form information text (not a string constant) which must conform to ITU-T V.250 format
rules. The information text will consist of at least four lines, containing the following information: 1) the number of bytes
of DCE memory available for buffering DTE-bound data, 2) the number of bytes of DCE memory available for buffering
WAN-bound data, 3) the amount of DTE-bound data buffered by the DCE, and 4) the amount of WAN-bound data
buffered by the DCE. Items 3 and 4 may be specified in bytes, packets, or other units selected by the manufacturer.
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The form of all information text output by the +WCMEM command is manufacturer-specific.
+WCMEM=? behaves according to ITU-T V.250 rules for action commands having no sub parameters.
Implementation
Implementation of this command is optional.
D.2.17. Flush WAN-bound Data Buffer
Parameter Syntax
+WCFLSH
+WCFLSH=?
Description
Flushes all WAN-bound data from the DCE. Behavior with respect to any partially-transmitted packets is manufacturerspecific.
+WCFLSH=? behaves according to ITU-T V.250 rules for action commands having no sub parameters.
Implementation
Implementation of this command is optional.
D.2.18. Display Supported Annex D Commands
Parameter Syntax
+WCXD
+WCXD=?
Description
This command allows the DCE to report back to the DTE which of the commands defined in this Annex it has
implemented.
When the DTE invokes this action (via +WCXD) the DCE must output the names of implemented PAD Control
Commands. Each name will be delimited by double quotes, the quoted strings being separated by commas. The list
includes the names of all supported Annex D commands, with the exception of +WCXD which is not reported. The
output may occupy multiple lines, following ITU-T V.250 rules for information text.
For example, a DCE operating supporting only the +WS60 and +WS61 commands (besides +WCXD) would respond to
+WCXD with:
“+WS60”,”+WS61”<end-of-info-text delimiter, e.g. CR/LF>
OK<delimiter>
+WCXD=? behaves according to ITU-T V.250 rules for action commands having no sub parameters.
Implementation
Implementation of this command is mandatory if any commands defined in this Annex are implemented.
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D.3. Additions to +W Command
This standard defines the mandatory +W command which reports a list of supported Standards and Annexes. DCE
which support any commands defined in this Annex must report the string +WCXD to the right of the string 101, and to
the left of the first string associated with any other standard.
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TIA-678-A
Appendix I. Command Set Summary (Informative)
The section summarizes all mandatory and optional DCE commands specified in this standard. All mandatory
commands in this table are part of the Common AT Command Set, and must be accessible in all DCE operating modes
(except On-Line Data State).
The columns of the summary table (below) are interpreted as follows:
Command
The Parameter Syntax of the command. Square brackets (e.g. [n]) represent Parameter
Syntax modifiers which may be used at the option of the DTE.
Argument / Values
If the command accepts a value (e.g. +IPR=n), this column lists the range of valid values.
Two consecutive periods indicate a range, while commas separate discrete values. A
double quote (ASCII 22 hex) indicates that the argument of values for this row are the
same as for the row immediately above. “mfr.-specific” indicates that the values accepted
by the command are manufacturer-specific.
Has Dflt.?
Indicates mandatory and recommended default values for parameters. An X indicates that
the Parameter Syntax in the Command column corresponds to the default value of the
parameter. An underlined value indicates a recommended default setting, and a bold
underlined entry indicates a mandatory default setting. Some commands have more than
one recommended default setting; the setting used by a given DCE typically results from
manufacturer-specific issues. An asterisk in this column indicates that this standard
establishes requirements for default setting of the parameter which cannot be expressed
in terms of mandatory or recommended default settings.
Req’d.?
An X in this column indicates that the DCE must recognize the Parameter Syntax in the
Command column, including accepting any value in the Argument / Values column.
Numbers in this column indicate the minimum set of parameter values that the DCE must
accept. The entry is blank for optional commands.
Reference
Identifies the reference document which provided the definition of the command used in
this standard.
Summary
A brief description of command operation and side-effects.
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TIA-678-A
Table I.17 - Command Set Summary
Command
Argument /
Values
Dflt. ?
&C
Req’d
?
X
Ref.
Summary
X
TIA/EIA602-A
“
“
TIA/EIA602-A
“
“
“
TIA/EIA602-A
“
“
TIA/EIA592-A
“
V.250
mfr.-specific
X
V.250
+GMR
mfr.-specific
X
V.250
+ICF=?
+ICF=[n[,m]]
(0-6),(0-3)
“
X
0 to 6
0 to 3
V.250
“
+ICF?
+IFC=?
+IFC=[n[,m]]
“
(0-3),(0-2)
“
“
V.250
“
+IFC?
+IPR=?
+IPR=[n]
“
0-255
“
X
X
0 to 3
0 to 2
X
X
1200
or
9600
“
V.250
“
Display current local flow control types
Display valid data rate options
Select Automatic or fixed DTE-DCE data rate.
NOTE: requirements derived from TIA/EIA-602A.
+IPR?
+W
+W=?
+WS45=?
+WS45=[n]
+WS45?
+WS46=?
+WS46=[n]
+WS46?
+WS60=[n]
+WS60?
+WS60=?
+WS62=[n]
“
X
X
X
X
X
X
X
X
X
X
X
X
X
“
Display current data rate
Test for claimed compliance with any standard.
Display list of supported standards.
Display valid DTE-Side Stack options
Select DTE-Side Stack
Display current DTE-Side Stack
Display valid WDS-Side Stack options
Select WDS-Side Stack
Display current WDS-Side Stack
Set Time-Independent Escape Sequence
Display current TIES setting
Display valid TIES settings
Set Local Online Echo
&C0
&C1
&D
X
&D0
&D1
&D2
&F
X
X
X
X
X
X
&F0
&Fn
+FCLASS=?
mfr.-specific
0-255, 2.0
+FCLASS=n
+GMI
“
mfr.-specific
+GMM
X
0-255
“
“
0-255
“
“
0,1
0,1
0,1
0,1
0
3,3
0 or 2,
0 or 2
0,
1200,
or
9600
*
*
0
0
Always assert RLSD
Always assert RLSD
RLSD changes in accordance with network
Ignore DTR
Ignore DTR
DTR on-to-off enters On-Line Command State
DTR on-to-off clears call
Set parameters to factory defaults
Set parameters to factory defaults
Reserved for manufacturer proprietary use
Display service class options
Select service class (voice / data / FAX)
DCE manufacturer identification. Action
command.
Manufacturer-specific DCE product identification.
Action command.
Model-specific DCE software revision
identification. Action command.
Display valid framing and parity options
Select Automatic or fixed DTE-DCE framing and
parity. NOTE: requirements derived from
TIA/EIA-602-A.
Display current framing and parity
Display valid local flow control options
Select local flow control type(s)
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TIA-678-A
Command
+WS62?
+WS62=?
+WS63=[n]
+WS63?
Argument /
Values
0-3
0-3
0-3
Dflt. ?
3
+WS63=?
+WS64=[n]
+WS64?
X
0-255
13
+WS64=?
+WS65=[n]
+WS65?
X
X
X
0-255
13
+WS65=?
+WS66=[n]
Req’d
?
X
X
X
X
X
X
X
0,1
1
X
+WS66?
X
+WS66=?
X
+WS67=[n]
+WS67?
+WS67=?
+WS68=[n]
+WS68?
+WS68=?
+WS69=[n]
+WS69?
+WS69=?
+WS70=[n]
+WS70?
+WS70=?
0-255
0
0-255
0
0,1,2
0
0-255
50
+WS71=[n]
+WS71?
+WS71=?
+WS72=[n]
+WS72?
0-255
0
0,1
0
+WS72=?
+WS73=[n]
+WS73?
X
X
X
X
X
X
0-255
8
+WS73=?
+WS74=[n]
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
mfr.-specific
255
X
Ref.
Summary
Display current Online Echo value
Display valie Online Echo settings
Set Forwarding Character Feature Mask
Display current Forwarding Character Feature
Mask value
Display valid Forwarding Character Feature
Mask values
Set PAD Primary Forwarding Character
Display current Forwarding Character Feature
Mask value
Display valid Forwarding Character Feature
Mask values
Set PAD Secondary Forwarding Character
Display current PAD Secondary Forwarding
Character value
Display valid PAD Secondary Forwarding
Character values
Set Packet Termination upon entering Online
Command State
Display current value of Packet Termination
variable
Display valid values for Packet Termination
variable
Set No Data Disconnect
Display current value of No Data Disconnect
Display valid No Data Disconnect values
Set Data Disconnect
Display current Data Disconnect value
Display valid Data Disconnect values
Set PAD Break Handling value
Display current PAD Break Handling value
Display valid PAD Break Handling values
Set PAD Inter-Character Timer
Display current PAD Inter-Character Timer
Display valid PAD Inter-Character Timer
values
Set PAD Inter-Line Timer
Display current PAD Inter-Line Timer values
Display valid PAD Inter-Line Timer values
Set PAD Input Buffer Editing Enable
Display current value of PAD Buffer Editing
Enable
Display valid PAD Buffer Editing Enable
values
Set PAD Input Buffer Backspace Character
Display current PAD Input Backspace
Character
Display valid PAD Input Backspace
Characters
Set PAD Maximum Packet Length
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Command
Argument /
Values
Dflt. ?
+WS74?
+WS74=?
+WCMEM
+WCMEM=?
+WCFLSH
+WCFLSH=?
+WCXD
Ref.
mfr.-specific
mfr.-specific
X
X
any string of
dial
modifiers
X
Display valid PAD Maximum Packet Lengths
Memory usage by PAD
Display memory usage by PAD
Flush all WAN-bound data
Display flushed WAN-bound data
Display names of implemented PAD Control
commands
TIA/EIA602-A
TIA/EIA602-A
E
X
E0
X
TIA/EIA602-A
“
X
“
X
TIA/EIA602-A
“
TIA/EIA602-A
TIA/EIA602-A
“
“
“
E1
X
H
H0
I[n]
X
mfr.-specific
L
X
L0
L1
L2
L3
M
X
X
X
X
X
M0
M1
M2
O
X
X
X
X
O0
X
On
P
mfr.-specific
X
X
Q
X
Q0
Q1
S0=[n]
0-255
S0?
“
X
0
X
X
0
X
Summary
Display PAD Maximum Packet Length
X
X
X
X
X
X
mfr.-specific
+WCXD=?
A
D[string][;]
Req’d
?
X
TIA/EIA602-A
“
“
“
TIA/EIA602-A
“
“
TIA/EIA602-A
TIA/EIA602-A
“
“
TIA/EIA602-A
“
Answer an incoming call.
Dial the remote end system identified by [string].
NOTE: operation of D with no string is
manufacturer-specific.
No echo in Command State and On-Line
Command State
No echo in Command State and On-Line
Command State
Echo characters in Command State and On-Line
Command State
Disconnect from line and terminate call
Disconnect from line and terminate call
Manufacturer specific identification commands
Set low speaker volume
Set low speaker volume
Set low speaker volume
Set medium speaker volume
Set high speaker volume
Speaker always off
Speaker always off
Speaker on until carrier detect
Speaker always on when off-hook
Go from On-Line Command State to On-Line
Data State
Go from On-Line Command State to On-Line
Data State
Manufacturer-specific
Select “pulse” dialing method.
DCE transmits result codes.
DCE transmits result codes.
DCE suppress result codes.
Select manual or automatic call answering.
Display current call answering setting
76
TIA-678-A
Command
S10=[n]
Argument /
Values
1-254
S10?
S3=[n]
“
0-127
S3?
“
S4=[n]
0-127
S4?
“
S5=[n]
0-127
S5?
“
S6=[n]
2-10
S6?
S7=[n]
“
1-255
S7?
S8=[n]
“
0-255
S8?
T
“
Dflt. ?
13
Req’d
?
X
X
X
X
10
X
X
8
X
X
2
X
X
X
2
X
X
X
X
Ref.
TIA/EIA602-A
“
TIA/EIA602-A
“
TIA/EIA602-A
“
TIA/EIA602-A
“
TIA/EIA602-A
“
TIA/EIA602-A
“
TIA/EIA602-A
“
TIA/EIA602-A
TIA/EIA602-A
V
X
V0
X
“
X
“
X
X
X0
X1
X2
X
X
X
TIA/EIA602-A
“
“
“
X3
X
“
X4
Z
X
X
“
TIA/EIA602-A
“
V1
Z[n]
X
mfr.-specific
X
Summary
Set automatic call disconnect delay.
Display automatic call disconnect delay.
Set ASCII code for command line termination
character.
Display ASCII code for command line termination
character.
Set ASCII code for response formatting
character.
Display ASCII code for response formatting
character.
Set ASCII code for command line editing
character.
Display ASCII code for command line editing
character.
Set pause interval before blind dialing
Display pause interval before blind dialing
Set connection completion time-out interval.
Display connection completion time-out interval.
Set duration of comma dialing delay.
Display duration of comma dialing delay.
Select “tone” dialing method.
DCE transmits limited headers and trailers with
numeric TIA/EIA-602-A result codes and
alphabetic extended result codes.
DCE transmits limited headers and trailers with
numeric TIA/EIA-602-A result codes and
alphabetic extended result codes.
DCE transmits full headers and trailers with
alphabetic result codes.
CONNECT, no dial tone or busy detection
CONNECT, no dial tone or busy detection
CONNECT <text>, no dial tone or busy detection
CONNECT <text>, dial tone detection but not
busy detection
CONNECT <text>, no dial tone detection but
busy detection
CONNECT <text>, dial tone and busy detection
Terminate any active call and set all parameters
to defaults.
Terminate any active call and set all parameters
to manufacturer-specific values. NOTE: the
manufacturer is allowed to differentiate between
Z and Z0.
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