PN-4078RV
(To be published as TIA/EIA-777A)
Telecommunications
Telephone Terminal Equipment
Caller Identity and Visual Message Waiting Indicator Equipment
Performance Requirements
Formulated under the cognizance of TIA Subcommittee TR-41.3
Analog and Digital Wireline Terminals
With the approval of TIA Engineering Committee TR-41
Telecommunication Equipment Requirements
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TABLE OF CONTENTS
1
SCOPE ............................................................................................................................. 9
2
NORMATIVE REFERENCES ............................................................................................ 9
3 ABBREVIATIONS, ACRONYMS, AND DEFINITIONS .................................................... 10
3.1 ABBREVIATIONS AND ACRONYMS ................................................................................... 10
3.2 DEFINITIONS ................................................................................................................. 10
4 TECHNICAL CRITERIA FOR CPE .................................................................................. 12
4.1 MANDATORY, RECOMMENDED, AND PERMISSIVE CRITERIA ............................................... 12
5 TYPE 1 CPE GENERAL .................................................................................................. 12
5.1 TYPE 1 CPE FUNCTIONALITY ......................................................................................... 12
5.2 TYPE 1 PROTOCOL......................................................................................................... 12
5.2.1 FSK following Power Ringing ..................................................................................... 12
5.2.2 FSK without Power Ringing ........................................................................................ 13
5.2.3 Time-out and Resetting Capabilities ............................................................................. 13
5.2.4 Type 1 Message Preamble ........................................................................................... 14
5.2.4.1 Channel Seizure Signal ............................................................................................ 14
5.2.4.2 Mark Signal ............................................................................................................ 14
5.2.4.3 Binary & ASCII encoding ........................................................................................ 14
5.2.5 Message Formats ....................................................................................................... 14
5.2.5.1 Message Types ....................................................................................................... 15
5.2.5.2 Message Length ...................................................................................................... 15
5.2.5.3 SDMF Message Type .............................................................................................. 15
5.2.5.3.1 SDMF Calling Number Parameter .......................................................................... 15
5.2.5.3.2 SDMF Reason for Absence of Calling Number ........................................................ 17
5.2.5.4 MDMF Message Format .......................................................................................... 17
5.2.5.4.1 Parameter Types .................................................................................................. 17
5.2.5.4.2 Parameter Length ................................................................................................. 18
5.2.5.4.3 Parameter Field Definitions ................................................................................... 18
5.2.5.4.3.1 MDMF Date and Time Parameter ....................................................................... 18
5.2.5.4.3.2 MDMF Calling Number Parameter...................................................................... 19
5.2.5.4.3.3 MDMF Dialable Directory Number Parameter...................................................... 19
5.2.5.4.3.4 MDMF Reason for Absence of Directory Number Parameter ................................. 20
5.2.5.4.3.5 MDMF Calling Name Parameter ......................................................................... 21
5.2.5.4.3.6 MDMF Reason for Absence of Name Parameter ................................................... 21
5.2.5.4.3.7 MDMF Call Qualifier Parameter ...................................................................... 22
5.2.5.4.3.8 Reason for Redirection Parameter (Reserved) ............................................... 23
5.2.5.5 Visual Message Waiting Indicator ......................................................................... 23
5.2.5.5.1 SDMF VMWI Parameter ...................................................................................... 23
5.2.5.5.2 MDMF VMWI Parameter ..................................................................................... 23
5.2.5.6 Mark Bits ............................................................................................................... 24
5.2.5.7 Checksum .............................................................................................................. 24
5.2.5.8 Markout ................................................................................................................. 24
5.2.6 Exception Handling .................................................................................................... 24
5.2.6.1 Checksum Error ...................................................................................................... 24
5.2.6.2 No Data Detected .................................................................................................... 24
1
5.2.6.3 Out of Range data ................................................................................................... 24
5.3 PHYSICAL LINE INTERFACE ............................................................................................ 25
5.3.1 FSK Signal Properties ................................................................................................ 25
5.3.1.1 Frequency .............................................................................................................. 25
5.3.1.2 Signal Levels .......................................................................................................... 25
5.3.1.3 Type 1 FSK Signal Level Detection Threshold ........................................................... 25
5.3.1.4 FSK Twist.............................................................................................................. 25
5.3.1.5 Baud Rate .............................................................................................................. 26
5.3.2 Impairments .............................................................................................................. 26
5.3.2.1 Single Tone Metallic Noise during FSK .................................................................... 26
5.3.2.2 Single Tone Metallic Noise before and after FSK ....................................................... 27
5.3.2.3 Type 1 - Echo Noise ................................................................................................ 27
5.3.2.4 Signal Dropouts During Channel Seizure ................................................................... 27
5.3.2.5 Immunity To Open Switching Intervals (OSIs) And Line Reversals .............................. 28
5.3.2.6 TYPE 1 OSI and Line Reversal Immunity .................................................................. 28
5.3.3 Type 1 DC operating Conditions.............................................................................. 28
5.3.4 Test Matrix for the FSK Signal Properties, Including Multiple Impairments ..................... 28
6 TYPE 2 PROTOCOL ....................................................................................................... 35
6.1 GENERAL ..................................................................................................................... 35
6.1.1 Type 2 CPE ............................................................................................................... 35
6.2 FUNCTIONALITY ........................................................................................................... 35
6.2.1 Type 2 Call Waiting Caller ID ..................................................................................... 35
6.2.2 CAS Detection .......................................................................................................... 36
6.2.2.1 CAS Detector Performance Recommendations ........................................................... 36
6.2.2.2 CAS Recognition .................................................................................................... 37
6.2.2.2.1 CAS Recognition Parameters ................................................................................ 37
6.2.2.2.2 CAS Recognition Test Matrix ............................................................................... 37
6.2.2.3 Talkdown Performance Parameters ........................................................................... 41
6.2.2.4 Talkoff Performance Parameters ............................................................................... 41
6.2.2.5 CAS Check Muting ................................................................................................. 42
6.2.3 CAS-ACK Handshake ................................................................................................ 43
6.2.3.1 Line and CPE States ................................................................................................ 43
6.2.3.2 CAS-ACK Handshake Protocol ................................................................................ 43
6.2.3.3 ACK Signal Generation ........................................................................................... 46
6.2.3.4 Voicepath Mute Control ........................................................................................ 46
6.3 TYPE 2 MARK SIGNAL ................................................................................................... 46
6.4 PHYSICAL LINE INTERFACE ............................................................................................ 46
6.4.1 FSK Signal Properties ................................................................................................ 46
6.4.1.1 Frequency .............................................................................................................. 46
6.4.1.2 Type 2 FSK Signal Level Detection Threshold ........................................................... 47
6.4.1.3 FSK Twist.............................................................................................................. 47
6.4.1.4 Baud Rate .............................................................................................................. 47
6.4.2 Impairments .............................................................................................................. 47
6.4.2.1 Single Tone Metallic Noise ...................................................................................... 47
6.4.2.2 Immunity To Open Switching Intervals (OSIs) And Line Reversals .............................. 48
6.4.2.3 TYPE 2 OSI and Line Reversal Immunity .................................................................. 48
6.4.3 TYPE 2 DC Operating Range .................................................................................. 48
6.4.4 Test Matrix for the FSK Signal Properties, Including Multiple Impairments ..................... 49
2
7 TYPE 2.5 PROTOCOL .................................................................................................... 55
7.1 GENERAL ..................................................................................................................... 56
7.1.1 Type 2.5 CPE .......................................................................................................... 56
7.2 FUNCTIONALITY............................................................................................................ 56
7.2.1 Type 2.5 Call Waiting Caller ID with Disposition .......................................................... 56
7.3 TYPE 2.5 MARK SIGNAL ................................................................................................. 56
7.3.1 CWD Options ............................................................................................................ 56
7.3.1.1 Answer .................................................................................................................. 56
7.3.1.2 Hold ...................................................................................................................... 56
7.3.1.2.1 Hold Return ......................................................................................................... 56
7.3.1.2.2 Hold Drop ........................................................................................................... 56
7.3.1.2.3 Conference .......................................................................................................... 56
7.3.1.3 Forward ................................................................................................................. 56
7.3.1.4 Announcement ........................................................................................................ 57
7.3.1.5 Drop ...................................................................................................................... 57
7.3.1.6 Conference ............................................................................................................. 57
7.3.1.6.1 Drop First ............................................................................................................ 57
7.3.1.6.2 Drop Last ............................................................................................................ 57
7.3.2 CWD Option Signals .................................................................................................. 57
7.3.2.1 CWD Flash Signal................................................................................................... 57
7.3.2.2 CWD DTMF Signal ................................................................................................ 57
7.3.2.3 CWD Option Signal Timing ..................................................................................... 57
7.3.3 Voicepath Mute Control During CWD Option Signaling ................................................ 58
8 ADJUNCT SERIES IMPEDANCE REQUIREMENTS ........................................................ 59
8.1 AC IMPEDANCE ............................................................................................................ 59
8.2 DC RESISTANCE............................................................................................................ 59
ANNEX A INFORMATIVE REFERENCES ............................................................................ 60
ANNEX B INFORMATIVE METHOD FOR RTF INTER-CPE SIGNALING ............................. 61
1.1 INTER-CPE SIGNALING ................................................................................................. 61
1.1.1 Request-to-Flash Signaling ..................................................................................... 61
1.1.1.1 Request-to-Flash Signal Generation ..................................................................... 61
1.1.1.2 Request-to-Flash Signal Detection and Response................................................ 63
ANNEX C INFORMATIVE CALCULATIONS ....................................................................... 65
ANNEX D EXAMPLES OF STEP-LIKE VOLTAGE CHANGES .............................................. 67
3
LIST OF FIGURES
Figure 1 – Timing for FSK following Power Ringing ................................................................ 13
Figure 2 – SDMF and MDMF Formats .................................................................................... 15
Figure 3 - SDMF Calling Number ........................................................................................... 17
Figure 4 - MDMF Date and Time Parameter ............................................................................. 19
Figure 5 - MDMF Calling Number Parameter ........................................................................... 19
Figure 6 - DDN Parameter ...................................................................................................... 20
Figure 7 - MDMF Reason for Absence of Directory Number Parameter ...................................... 21
Figure 8 - MDMF Calling Name Parameter .............................................................................. 21
Figure 9 - MDMF Reason for Absence of Name Parameter ........................................................ 22
Figure 10 - MDMF Call Qualifier Parameter ............................................................................ 23
Figure 11 - SDMF Visual Message Waiting Indicator Parameter ................................................. 23
Figure 12 - MDMF Visual Message Waiting Indicator Parameter ............................................... 24
Figure 13 – CAS-ACK Handshake Diagram ............................................................................. 45
Figure 24 - CWD State Diagram ............................................................................................. 58
Figure 25 - CWD Signaling Timing Diagram ............................................................................ 59
Figure 26 - CPE State Generating RTF, Multiple CPE Off-Hook, Successful Synchronized Flash .. 61
Figure 27 - Line State During RTF, Multiple CPE Off-Hook, Successful Synchronized Flash ........ 62
Figure 28 - Line State During RTF, Single CPE Off-Hook ......................................................... 62
Figure 29 - CPE State Generating RTF, Multiple CPE Off-Hook, And Unsuccessful RTF ............. 62
Figure 30 - Line State During RTF, Multiple CPE Off-Hook, And Unsuccessful RTF ................... 63
Figure 31 - CPE State Detecting & Responding to an RTF, Successful Synchronized Flash ........... 63
Figure 32 - Line State During RTF, Multiple CPE Off-Hook, Successful Synchronized Flash ........ 63
Figure 33 - CPE State Detecting & Responding to an RTF, Unsuccessful RTF ............................. 64
Figure 34 - Line State During RTF, Multiple CPE Off-Hook, Unsuccessful RTF .......................... 64
4
LIST OF TABLES
Table 1 - Message Type Values ............................................................................................. 15
Table 2 - Parameter Type Values ............................................................................................. 17
Table 3 - Type 1 FSK Positive Twist Acceptance Values ........................................................... 26
Table 4 - Type 1 FSK Negative Twist Acceptance Values .......................................................... 26
Table 5 - Type 1 Single Tone Noise Requirements .................................................................... 27
Table 6 - Group A, Variable Level Sensitivity Tests – Type 1 ..................................................... 28
Table 7 - Group B, Twist Test - Nominal Otherwise – Types 1 ................................................... 29
Table 8 - Group C, Combined Impairments - Frequencies, Baud, and Twist – Type 1 .................... 29
Table 9 - Group E, Noise Tests – Type 1 (Noise applied during FSK only) .................................. 32
Table 10 - Group F, Noise Tests – Type 1 with +10 dB FSK Twist ............................................. 33
Table 11 - Group G, Noise Tests – Type 1 with –6 dB FSK Twist ............................................... 34
Table 12 – Group H, Echo Noise Type 1 .................................................................................. 35
Table 13 - Group I, Send without Ringing-Shall Reject Calls – Type 1 ........................................ 35
Table 14 - CAS Parameter Limits ............................................................................................ 37
Table 15 - Group 1, CAS Recognition - All Parameters at Nominal Values .................................. 38
Table 16 - Group 2, CAS Recognition - One Parameter at a Time at the Extreme Value................. 38
Table 17 - Group 3, CAS Recognition - Parameters at 90% from Nominal, 75.5 ms CAS ............... 39
Table 18 - Group 3, CAS Recognition - Parameters at 90% from Nominal, 84.5 ms CAS ............... 40
Table 19 - Group 4, CAS Reject Amplitude .............................................................................. 40
Table 20 - Type 2 FSK Positive Twist Acceptance Values ......................................................... 47
Table 21 - Type 2 FSK Negative Twist Acceptance Values ........................................................ 47
Table 22 - Type 2 Single Tone Noise Requirements................................................................... 48
Table 23 - Group A, Variable Level Sensitivity Tests – Type 2 ................................................... 49
Table 24 - Group B, Twist Test - Nominal Otherwise – Type 2 ................................................... 49
Table 25 - Group E, Noise Tests – Type 2 (Noise on during FSK only) ........................................ 53
Table 26 - Group F, Noise Tests – Type 2 with +10 dB FSK Twist ............................................. 54
Table 27 - Group G, Noise Tests – Type 2 with –6 dB FSK Twist ............................................... 55
5
FOREWORD
(This foreword is not part of this standard.)
This document is a TIA/EIA Telecommunications standard produced by Working Group TR-41.3.1
of Committee TR-41. This standard was developed in accordance with TIA/EIA procedural
guidelines, and represents the consensus position of the Working Group and its parent Subcommittee
TR-41.3, which served as the formulating group. Some of the requirements contained in this
standard are based on information obtained from external organizations, including Telcordia
Technologies (formerly Bellcore), Stentor, ANSI, and others. The Working Group gratefully
acknowledges the cooperation and support of these external organizations.
Annexes A & B are informative only, and are not considered part of this standard.
Suggestions for improvement of this standard are welcome. They should be sent to:
Telecommunications Industry Association
Engineering Department
Suite 300
2500 Wilson Boulevard
Arlington, VA 22201
6
TR-41.3.1 Working Group
TECHNICAL CONTRIBUTORS .......................................................... ORGANIZATION REPRESENTED
David Stenner (Editor) - ............................................................... Advent Instruments Inc.
James Bress - ................................................................................ AST Technology Labs
Trone Bishop - .............................................................................. Bell Atlantic
Rick White - ................................................................................. CIDCO
Harry Van Zandt - ........................................................................ ECS Technologies
Len Bleile (Chair) - ...................................................................... Embedded Systems Products
Ken Macdonald - .......................................................................... Microtronix Systems Ltd
Philip Ching - ............................................................................... Mitel Corp.
James Kemerling - ........................................................................ Mx-Com
Greg Neal (Editor) - ..................................................................... Notify Corp.
Rick Carey - .................................................................................. Radio Shack
Stan Pietrowicz - .......................................................................... Telcordia Technologies
Al Baum - ..................................................................................... Uniden
Steve Whitesell - .......................................................................... VTech Innovations
PARTICIPANTS................................................................................ ORGANIZATION REPRESENTED
Don McKinnon - ........................................................................... AST Technology Labs
Jim Mazzolini - ............................................................................. Casio Communications
David Luneau - ............................................................................. ClassCo Inc.
John Riley - .................................................................................. DSP Software Engineering
Yuan Fan - .................................................................................... Fanstel
Scott Early - .................................................................................. InDesign
William Becker - .......................................................................... Lucent
Roger Britt, Jerry Freestone - ....................................................... Nortel Networks
Michael Menard - ........................................................................ Qwest
Ron Magnuson - ........................................................................... Siemens
Yoshi Egami - ............................................................................... Sony
Amar Nath Ray - .......................................................................... Sprint Local Telephone Division
John Balinski - .............................................................................. Telcordia
Julian Lee, Steve Kropp - ............................................................. VTech Engineering
Mabel Au, Mark Yuen - ............................................................... VTech Communications Ltd.
Larry Bell - ................................................................................... Wyle Labs
7
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8
1 SCOPE
This standard addresses the technical issues associated with Type 1, Type 2, and Type 2.5
Caller Identity Customer Premises Equipment for services such as Calling Identity Delivery, Calling
Identity Delivery on Call Waiting and Call Waiting Deluxe. The Type 1 and Type 2 issues were
previously addressed in TIA/EIA-716 and TIA/EIA-777 respectively. The services use On-Hook and
Off-Hook signaling with data frames packaged in Single Data Message Format (SDMF), and
Multiple Data Message Format (MDMF). Specifically, this standard establishes formal criteria for
the signals and protocol that the CPE should be capable of receiving.
This standard is not in any way intended to be a guideline for switch suppliers or a Network Interface
requirement.
2 NORMATIVE REFERENCES
The following standards contain provisions 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.
ANSI and TIA maintain registers of currently valid national standards published by them.
1) ANSI T1.401-2000, American National Standard for Telecommunications - Interface between
Carriers and Customer Installations - Analog Voicegrade Switched Access Lines Using LoopStart and Ground-Start Signaling.
2) ANSI T1.401.02-1995, American National Standard for Telecommunications - Interface
between Carriers and Customer Installations - Analog Voicegrade Switched Access Lines With
Distinctive Alerting Features.
3) ANSI/TIA/EIA-470-B-1997, Telecommunications - Telephone Terminal Equipment –
Performance and Compatibility Requirements for Telephone Sets with Loop Signalling.
4) Telcordia Technologies
Transmission Interface.
GR-30-CORE, Issue 2, December 1998, Voiceband Data
5) Telcordia Technologies SR-3004, Issue 2, January 1995, Testing Guidelines for Analog Type
1,2, and 3 CPE as Described in SR-INS-002726.
6) Telcordia Technologies SR-INS-002726, Issue 1, August 1993, Classes of Customer Premises
Equipment
7) Telcordia Technologies SR-TSV-002476, Issue 1, December 1992, (plus Bulletin No. 1,
September 1993), Customer Premises Equipment Compatibility Considerations for the
Voiceband Data Transmission Interface
8) ITU – Recommendations P.56 (03/93) - Objective Measurement of Active Speech Level.
9) ANSI X3.4-1977, Code for Information Interchange.
10) STENTOR ID-0012 May 1992, Enhanced Call Management Service (ECMS), Terminal-toNetwork Interface.
9
3
3.1
ABBREVIATIONS, ACRONYMS, AND DEFINITIONS
Abbreviations and Acronyms
For the purposes of this Standard, the following abbreviations and acronyms apply.
ACK: Acknowledgment Signal
ADSI: Analog Display Services Interface
CAS: CPE Alerting Signal
CIDCW: Calling Identity Delivery on Call Waiting
CNAM: Calling Name Delivery
CND: Calling Number Delivery
CPE: Customer Premises Equipment
CWD: Call Waiting Deluxe
DDN: Dialable Directory Number
DN: Directory Number
FSK: Frequency Shift Keying
MDMF: Multiple Data Message Format
OSI: Open Switch Interval
RTF: Request-to-Flash
SAS: Subscriber Alerting Signal
SDMF: Single Data Message Format
VMWI: Visual Message Waiting Indicator
3.2
Definitions
For the purposes of this Standard, the following definitions apply.
ACK-Sender: The single CPE that will complete the CAS-ACK handshake and terminate the line
during data transmission if no incompatible extension is detected.
ACK Signal: The signal used by a CPE to ACKnowledge the receipt of a CAS.
Checksum: The last byte of an SDMF/MDMF message, which is used as a simple method for the
detection of errors. It is calculated as the 2’s complement of the modulo 256 sum of all bytes in the
message excluding the checksum byte.
CPE Alerting Signal: The signal that informs the Type 2 CPE that there is a Call Waiting.
CPE State: The condition of the telephone device. It can be either On-Hook or Off-Hook.
Flash: A Line High condition generated by CPE, lasting from 300 ms to 1000 ms, used as a signal to
the Central Office switch.
Line State: The condition of the Tip and Ring interface. It can be either In-Use or High.
Listening-Path: The path from electrical signals at Tip & Ring to acoustic signals at the CPE
receiver/speaker.
Mark: A logical ‘1’ for FSK signaling.
10
Message Length: The second byte in an SDMF/MDMF message that indicates the length of the
Message (in bytes) excluding the Message Type byte, Message Length byte, and the Checksum byte.
Message Type: The first byte in an SDMF/MDMF message used to indicate the type of Message.
Parameter Length: The second byte in an MDMF Parameter message that indicates the length of
the Parameter Message excluding the Parameter Type byte and the Parameter Length byte.
Parameter Message: A block of bytes in an MDMF message that starts with a Parameter Type and
ends with the last Parameter Word for the given Parameter Message.
Parameter Type: The first byte in an MDMF Parameter Message that indicates the type of the
Parameter Message.
Parameter Word: Each data byte that follows the Parameter Type byte and Parameter Length byte
in a Parameter Message up to the next Parameter Type byte or Checksum.
Request-to-Flash: A timed DC signal that is used to modulate the DC line voltage to signal an
attempt to orchestrate a synchronized period where all CPE proceed to the On-Hook state to generate
a Flash signal.
Space: A logical ‘0’ for FSK signaling.
Subscriber Alerting Signal: A signal that informs the customer that there is a Call Waiting.
Talking-Path: The path from acoustic signals at the CPE microphone to electrical signals at Tip &
Ring.
FSK Twist:

The power differential of the Mark and Space signal amplitudes for FSK signals. FSK Twist is
positive when the Mark signal amplitude is higher than the Space signal amplitude.

The power differential between tones of a dual tone signal (e.g. CAS). Dual tone Twist is
positive when the lower frequency tone amplitude is greater than the higher frequency tone
amplitude.
Type 3 CPE: An Analog Display Services Interface (ADSI) capable terminal
Type 3 Assertion Signal: A DC signal used to modulate the DC line voltage to signal the current
ACK-Sender to relinquish its role as ACK-Sender.
Voicepath: A path that collectively consists of a Talking-Path and a Listening-Path.
11
4
TECHNICAL CRITERIA FOR CPE
4.1
Mandatory, Recommended, and Permissive Criteria
Three types of criteria are specified in this standard: Mandatory, Recommended and Permissive.
5

Mandatory criteria are designated by the terms “shall” and “shall not”. These criteria are
used to indicate requirements for which no deviation is permitted.

Recommended criteria are designated by the terms “should” and “should not”. These criteria
are used to identify compatibility or performance advantages towards which future designs
should strive.

Permissive criteria are designated by the terms “may” and “may not”. These criteria are used
to identify an action that is permitted within the limits of the standard.
TYPE 1 CPE GENERAL
Type 1 Customer Premises Equipment (CPE) supports On-Hook signaling with or without power
ringing and is able to decode data frames packaged in a Single Data Message Format (SDMF) or a
Multiple Data Message Format (MDMF).
Examples:
1) Calling Number Delivery (CND) may be transmitted to the CPE in the SDMF or MDMF. All
CND deliveries are currently associated with power ringing.
2) Calling Name Delivery (CNAM) is always transmitted in the MDMF with power ringing.
3) Visual Message Waiting Indicator (VMWI) may be transmitted to the CPE in the SDMF or
MDMF. The Frequency Shift Keying (FSK) versions of VMWI are sent with no power ringing,
or due to limitations in pair gain systems, following an abbreviated Ring.
5.1
Type 1 CPE Functionality
Type 1 CPE shall perform three major functions. These functions include:
1) Detection of FSK signals over a range dictated by the combination of switching system, loop
plant and pair gain system performance. Such detection takes place in an environment that could
introduce noise and other distorting elements.
2) Decoding of individual information fields, verification of their contents and finally error
checking of the entire message for accuracy.
3) Translation and presentation of the binary formatted data in a language the user can understand.
5.2
5.2.1
Type 1 Protocol
FSK following Power Ringing
For switching features that precede FSK data with power ringing, such as CND and CNAM, the
following shall apply:
1) Type 1 CPE shall be ready to receive FSK data commencing between 250 ms and 3600 ms
following the end of power ringing.
2) Type 1 CPE shall be able to receive FSK data preceded by the ringing patterns described in
ANSI T1.401.02-1995.
3) Type 1 CPE shall not log or display any type of error message for the following events:
12

Power ringing signals < 100ms.

Dial Pulse signals.

Transients due to On-Hook and Off-Hook transitions, except during data reception.
4) Type 1 CPE shall tolerate shifts in dc voltage or voltage reversals occurring on the line prior to
the start of FSK data.
The timing event is illustrated in Figure 1.
250 ms to
3.6 Sec
> 200 ms
Variable
st
nd
1
Power
Ring
Pattern
FSK Data
2
Power
Ring
Pattern
Figure 1 – Timing for FSK following Power Ringing
5.2.2
FSK without Power Ringing
If the CPE supports VMWI, it shall be able to receive FSK data that is not preceded with power
ringing, Open Switch Intervals (OSI), or line polarity reversals.
5.2.3
Time-out and Resetting Capabilities
If a message does not appear to end due to extended Markout (see section 5.2.5.8), interference, or
other similar reasons, Type 1 CPE may terminate the receive sequence of the current message 10
seconds after the end of the “on” period of the last power ringing pattern. This provides for power
conservation in battery-powered devices.
If the message was not preceded by power ringing, the CPE may terminate the receive sequence of
the current message 10 seconds after the receipt of 70 bits of channel seizure signal.
Type 1 devices that support on-hook data transmission without power ringing shall be capable of
receiving a data message not preceded by power ringing where the FSK data message begins at least
6 seconds after a previous power ringing event, given the telephone line remains in the idle state.
Type 1 devices that support on-hook data transmission with power ringing shall be capable of
receiving a data message preceded by power ringing where the power ringing burst begins at least 6
seconds after a previous power ringing event, given the telephone line remains in the idle state.
Type 1 devices that support on-hook data transmission without power ringing shall be capable of
receiving a data message not preceded by power ringing where the FSK data message begins at least
500 ms after the telephone line returns to an idle voltage from an active state.
13
Type 1 devices that support on-hook data transmission with power ringing shall be capable of
receiving a data message preceded by power ringing where the power ringing burst begins at least
500 ms after the telephone line returns to an idle voltage from an active state.
5.2.4
Type 1 Message Preamble
The message preamble consists of Channel Seizure followed by Mark Signal.
5.2.4.1
Channel Seizure Signal
Type 1 CPE shall, at a minimum, accept On-Hook messages that start with a Channel Seizure Signal
(normally a block of 300 continuous bits of alternating Mark “1” and Space “0”) whose contiguous
length is between:

70 and 320 bits.
Type 1 CPE shall ignore any Mark bits that precede the Channel Seizure Signal
5.2.4.2
Mark Signal
Type 1 CPE shall, at a minimum, accept On-Hook messages that are preceded by a Mark Signal
(normally a block of 180 bits of Mark) whose contiguous length is between:

5.2.4.3
40 and 525 bits.
Binary & ASCII encoding
Message Types, Parameter Types, Message Lengths, and Parameter Lengths are encoded in Binary
format.
Parameter Words are encoded in ASCII format, with the exception of MDMF VMWI data field,
which is encoded in full Binary, format and are sent as least significant bit first.
5.2.5
Message Formats
Switching systems transmit feature data in one of two formats, SDMF or MDMF. On-Hook CND
could be transmitted in either format. VMWI could also be transmitted in either format. All OffHook features and On-Hook CNAM are transmitted in MDMF only. CPE shall support both SDMF
and MDMF, as illustrated in Figure 2 – SDMF and MDMF Formats. Each byte is sent least
significant bit first. Each byte is preceded by a start bit (Space) and followed by a stop bit (Mark).
SDMF
MDMF
1 Byte (8 bits)
1 Byte (8 bits)
Preamble
Preamble
Message Type
Message Type
Mark Bits (0-100)
Mark Bits (0-100)
Message Length
Message Length
Mark Bits (0-100)
Mark Bits (0-100)
Message Word
Parameter Type
Mark Bits (0-100)
Mark Bits (0-100)
More Message Words
Parameter Length
Mark Bits (0-100)
Mark Bits (0-100)
Checksum
Parameter Word
14
Markout
Mark Bits (0-100)
More Parameter Words
Mark Bits (0-100)
More Parameter Messages
Mark Bits (0-100)
Checksum
Markout
Figure 2 – SDMF and MDMF Formats
5.2.5.1
Message Types
For supported features, CPE shall recognize the Message Type values described in Table 1. The
Message Type is a single 8-bit field. CPE shall continue to detect and display supported Message
Types and ignore the unsupported Message Types.
Table 1 - Message Type Values
Message Type
Message Type Value
Format
Calling Number Delivery
Visual Message Waiting Indicator
Call Setup
Service Test *1
Visual Message Waiting Indicator
Manufacturer-Specific Testing (reserved) *2
04 hex
06 hex
80 hex
81 hex
82 hex
4C hex to 6C hex
SDMF
SDMF
MDMF
MDMF
MDMF
NONE
*1 - The Service Test Message Type may be used at some locations, refer to Stentor ID-0012.
*2 - A range of Message Type values has been reserved for manufacturer-specific testing. Any
Message Type values used for such testing purposes should be limited to the specified range of
Message Type values to prevent conflict with future service definitions. The reserved Message Type
value range was chosen such that a single bit-flip error in the Message Type of current services does
not activate the testing routine.
5.2.5.2
Message Length
The Message Length received in the data message shall be used to count off the number of bytes
contained in the message. Hard-coded values for the Message Length shall not be substituted for the
received values. The Message Length is a single byte.
The CPE shall verify the Message Length is equal to the total number of bytes following the Message
Length byte prior to the Checksum. The Message Length does not include the Checksum.
5.2.5.3
5.2.5.3.1
SDMF Message Type
SDMF Calling Number Parameter
For SDMF CND, the CPE shall decode a Message Type value 04 hex as the Calling Number
Delivery message. The length of this message is expected to vary. The most significant byte will be
received first. See Figure 3.
15
This message always starts with the Time and Date and concludes with either the Calling number or
the Reason for Absence of Calling Number.

In this message, the CPE shall support the numeric ASCII characters in this field. The CPE
shall be able to decode and display 30 hex through 39 hex.

The CPE shall decode the binary-represented Message Length to count off the ensuing data
words.

The CPE shall decode the first two bytes as the month information. The first byte of the
month information is the 10’s position (Valid Range 0-1 [30 hex and 31 hex]). The second
byte of the month information is the 1’s position (Valid Range 0-9 [30 hex and 39 hex]). The
combined month information has a valid range of 1 through 12.

The CPE shall decode the next two bytes (3rd and 4th) as the day information. The third byte
is the day information, 10’s position (Valid Range 0-3 [30 hex and 33 hex]). The fourth byte
is the day information, 1’s position (Valid Range 0-9 [30 hex and 39 hex]). The combined
day information has a valid range of 1 through 31.

The CPE shall decode the next two bytes (5th and 6th) as the hour information in 24-hour
format. The fifth byte is the hour information, 10’s position (Valid Range 0-2 [30 hex and 32
hex]). The sixth byte is the hour information, 1’s position (Valid Range 0-9 [30 hex and 39
hex]). The combined hour information has a valid range of 0 through 23.

The CPE shall decode the next two bytes (7th and 8th) as the minute information. The
seventh byte is the minute information, 10’s position (Valid Range 0-5 [30 hex and 35 hex]).
The eighth byte is the minute information, 1’s position (Valid Range 0-9 [30 hex and 39
hex]). The combined minute information has a valid range of 0 through 59.

The CPE shall decode the rest of the data words as the Calling Number information
(typically 10 bytes).

The CPE should receive, but not necessarily display, up to 24 digits for the Calling Number
Parameter.
16
8
7
6
5
4
3
2
1
Message Type 04 hex
Message Length (N) hex
1
‘Month’ Message Word
2
‘Month’ Message Word
.
‘Day’ Message Word
.
‘Day’ Message Word
.
‘Hour’ Message Word
.
‘Hour’ Message Word
.
‘Minute’ Message Word
‘Minute’ Message Word
.
st
1 Calling Number Word OR
Reason for Absence of Calling Number
N
Nth Calling Number Word
Figure 3 - SDMF Calling Number
5.2.5.3.2
SDMF Reason for Absence of Calling Number
Reason for absence of the calling number is indicated by a 50 hex for a blocked number and 4F hex
for an unavailable number.

The CPE shall support a blocked number indication.

The CPE shall support an unavailable number indication.
5.2.5.4
5.2.5.4.1
MDMF Message Format
Parameter Types
For supported features, CPE shall recognize the Parameter Type values described in Table 2. The
Parameter Type is a single byte.
Table 2 - Parameter Type Values
Parameter Type
Parameter Type Value
Date & Time
Calling Number
Dialable Directory Number
Reason for Absence of Directory Number
Reason for Redirection (reserved)
Call Qualifier
Calling Name
01 hex
02 hex
03 hex
04 hex
05 hex
06 hex
07 hex
17
Reason for Absence of Calling Name
Visual Message Waiting Indicator
08 hex
0B hex
If a CPE detects an unknown Parameter Type, it shall ignore that Parameter Message and proceed to
check the subsequent Parameter Messages in the MDMF message. New services are expected to
include new Parameter Messages in the MDMF message. CPE shall decode and display supported
parameters and ignore any unsupported parameters. CPE shall process the parameter blocks within
an MDMF message regardless of the order of the parameter messages.
5.2.5.4.2
Parameter Length
The Parameter Length received in the data shall be used to count off the number of bytes contained
in each Parameter Message. Hard-coded values for the Parameter Lengths shall not be substituted
for the received values. The Parameter Length is a single byte. An incorrect Parameter Length may
result in a Checksum error.
5.2.5.4.3 Parameter Field Definitions
5.2.5.4.3.1 MDMF Date and Time Parameter
CPE shall decode a Parameter Type value 01 hex as the date and time parameter. The length of this
parameter is 8 bytes. The most significant byte will be received first. See Figure 4 - MDMF Date
and Time Parameter.

CPE shall decode the first two bytes as the month information. The first is the 10’s position
(Valid Range 0-1 [30 hex and 31 hex]). The second byte is the 1’s position (Valid Range 0-9
[30 hex through 39 hex]). The combined month information has a valid range of 1 through
12.

CPE shall decode the next two bytes (3rd and 4th) as the day information. The third byte is
the 10’s position (Valid Range 0-3 [30 hex through 33 hex]). The fourth byte is the 1’s
position (Valid Range 0-9 [30 hex through 39 hex]). The combined day information has a
valid range of 1 through 31.

CPE shall decode the next two bytes (5th and 6th) as the hour information in 24-hour format.
The fifth byte is the 10’s position (Valid Range 0-2 [30 hex through 32 hex]). The sixth byte
is the 1’s position (Valid Range 0-9 [30 hex through 39 hex]). The combined hour
information has a valid range of 0 through 23.

CPE shall decode the next two bytes (7th and 8th) as the minute information. The seventh
byte is the 10’s position (Valid Range 0-5 [30 hex through 35 hex]). The eighth byte is the
1’s position (Valid Range 0-9 [30 hex through 39 hex]). The combined minute information
has a valid range of 0 through 59.
8
7
6
5
4
Parameter Type 01 hex
Parameter Length 08 hex
1
‘Month’ Parameter Word
2
‘Month’ Parameter Word
18
3
2
1
.
‘Day’ Parameter Word
.
‘Day’ Parameter Word
.
‘Hour’ Parameter Word
.
‘Hour’ Parameter Word
.
‘Minute’ Parameter Word
8
‘Minute’ Parameter Word
Figure 4 - MDMF Date and Time Parameter
5.2.5.4.3.2 MDMF Calling Number Parameter
CPE shall decode a Parameter Type value 02 hex as the Calling Number parameter. The length of
this parameter is typically 10 bytes. The most significant byte will be received first. See Figure 5 MDMF Calling Number Parameter

CPE shall decode the binary-represented Parameter Length to count off the number of
ensuing Parameter Words.

CPE shall support the numeric ASCII characters 0-9 (30 hex through 39 hex) as valid
Parameter Words.

CPE shall be able to display at least 10 digits for the Calling Number parameter.

CPE should receive, but not necessarily display, up to 24 digits for the Calling Number
parameter.
8
7
6
5
4
3
2
1
Parameter Type 02 hex
Parameter Length (N) hex
1
Parameter Word
2
Parameter Word
Parameter Word
Parameter Word
N
Parameter Word
Figure 5 - MDMF Calling Number Parameter
5.2.5.4.3.3 MDMF Dialable Directory Number Parameter
The Dialable Directory Number (DDN) parameter is different from the Calling Number parameter in
one respect. It provides the exact string of digits that must be dialed to reach the calling number.
Therefore, if the customer only needs to dial 7 digits to reach the caller, the switch only sends those 7
digits.
19
CPE shall decode a Parameter Type value 03 hex as the DDN parameter. The length of this
parameter is expected to vary up to 11 bytes. The most significant byte will be received first. See
Figure 6.

CPE shall decode the binary-represented Parameter Length to count off the number of
ensuing Parameter Words.

CPE shall support the numeric ASCII characters 0-9 (30 hex through 39 hex) as valid
Parameter Words.

CPE shall be able to display at least 11 digits for the DDN parameter.

CPE should receive, but not necessarily display, up to 24 digits for the international DDN
parameter.

If both the Calling Number parameter and the DDN parameter are received in the same Call
Setup message, CPE should display the DDN instead of the Calling Number unless it has the
ability to display both.
8
7
6
5
4
3
2
1
Parameter Type 03 hex
Parameter Length (N) hex
1
Parameter Word
2
Parameter Word
Parameter Word
Parameter Word
N
Parameter Word
Figure 6 - DDN Parameter
5.2.5.4.3.4 MDMF Reason for Absence of Directory Number Parameter
Both blocked number and unavailable number indications have special parameter messages in
MDMF. CPE shall expect to receive this parameter in place of the Calling Number or DDN
parameters. These parameters are received when the information about the caller is not available to
the switch or if the caller had opted to place the call and block the number.
CPE shall decode a Parameter Type value 04 hex as the Reason for Absence of Directory Number
parameter. The length of this parameter is 1 byte. See Figure 7.

CPE shall decode the binary-represented Parameter Length to count off the number of
ensuing Parameter Words.

CPE shall support receipt of a Parameter Word consisting of an ASCII “P” (50 hex) as a
blocked number indication.

CPE shall support receipt of a Parameter Word consisting of an ASCII “O” (4F hex) as an
unavailable number indication.
20
8
7
6
5
4
3
2
1
Parameter Type 04 hex
Parameter Length 01 hex
1
4F Hex or 50 hex
Figure 7 - MDMF Reason for Absence of Directory Number Parameter
5.2.5.4.3.5 MDMF Calling Name Parameter
CPE shall decode a Parameter Type value 07 hex as the Calling Name parameter. The length of this
parameter is expected to vary up to 15 bytes, with a possibility of expanding up to 21 bytes for
international name. The most significant byte will be received first. See Figure 8.

CPE shall decode the binary-represented Parameter Length to count off the number of
ensuing Parameter Words.

CPE shall receive all the printable ASCII characters in this field. CPE shall be able to decode
ASCII characters represented by 20 hex through 7E hex.

CPE shall display the first byte of the Calling Name parameter as the leftmost character in
the name display field.

CPE shall be able to display at least 15 characters for the Calling Name parameter.

CPE should receive, but not necessarily display, up to 21 characters for the Calling Name
parameter.
8
7
6
5
4
3
2
1
Parameter Type 07 hex
Parameter Length (N) hex
1
Parameter Word
2
Parameter Word
Parameter Word
Parameter Word
N
Parameter Word
Figure 8 - MDMF Calling Name Parameter
5.2.5.4.3.6 MDMF Reason for Absence of Name Parameter
CPE shall expect to receive this parameter in place of the Calling Name parameter. This parameter is
received when the caller name is not available to the switch or if the caller has opted to block the
name.
21
CPE shall decode a Parameter Type value 08 hex as the Reason for Absence of Calling Name
parameter. The length of this parameter is 1 byte. See Figure 9.

CPE shall decode the binary-represented Parameter Length to count off the number of
ensuing Parameter Words.

CPE shall support receipt of a Parameter Word consisting of an ASCII “P” (50 hex) as a
blocked name indication.

CPE shall support receipt of a Parameter Word consisting of an ASCII “O” (4F hex) as an
unavailable name indication.
It is possible that CPE may receive a reason for absence of number parameter along with a valid
name or vice versa.

Information associated with Parameter Type 04 shall only apply to the display of the Reason
for Absence of Calling Number.

Information associated with Parameter Type 08 shall only apply to the display of the Reason
for Absence of Calling Name.
8
7
6
5
4
3
2
1
Parameter Type 08 hex
Parameter Length 01 hex
1
4F hex or 50 hex
Figure 9 - MDMF Reason for Absence of Name Parameter
5.2.5.4.3.7 MDMF Call Qualifier Parameter
The Call Qualifier parameter may be sent in the Call Setup message to indicate to the customer that
the incoming call is a toll call. There may be toll charges associated with returning a call to that
number. Refer to Stentor ID-0012.
CPE shall decode a Parameter Type value 06 hex as the Call Qualifier parameter. The length of this
parameter is 1 byte. See Figure 10.

CPE shall decode the binary-represented Parameter Length to count off the number of
ensuing Parameter Words.

CPE shall support receipt of a Parameter Word consisting of an ASCII “L” (4C hex) as the
call qualifier indication.
8
7
6
5
4
Parameter Type 06 hex
Parameter Length 01 hex
22
3
2
1
1
4C hex
Figure 10 - MDMF Call Qualifier Parameter
5.2.5.4.3.8 Reason for Redirection Parameter (Reserved)
This parameter is reserved for future use and has not been defined.
5.2.5.5 Visual Message Waiting Indicator
5.2.5.5.1
SDMF VMWI Parameter
For SDMF VMWI, the CPE shall decode a Message Type value 06 hex as the Message Waiting
Indicator message. The length of that message is 3 bytes. See Figure 11.

The CPE shall decode the binary-represented Message Length to count off the ensuing data
words.

The CPE shall interpret three consecutive bytes of 42 hex as a request to turn the notification
ON. Similarly, the CPE shall interpret three consecutive bytes of 6F hex as a request to turn
the notification OFF.
8
7
6
5
4
3
2
1
Message Type 06 hex
Message Length 03 hex
1
42 hex or 6F hex
2
42 hex or 6F hex
3
42 hex or 6F hex
Figure 11 - SDMF Visual Message Waiting Indicator Parameter
5.2.5.5.2
MDMF VMWI Parameter
CPE shall decode a Parameter Type value 0B hex as the Visual Message Waiting Indicator (VMWI)
parameter. The length of this parameter is one byte. See Figure 12.

CPE shall decode the binary-represented Parameter Length to count off the number of
ensuing Parameter Words.

CPE shall interpret the Parameter Word FF hex as a request to turn notification ON.
Similarly, the CPE shall interpret Parameter Word 00 hex as a request to turn the notification
OFF.
8
1
7
6
5
4
Parameter Type 0B hex
23
3
2
1
2
Parameter Length 01 hex
3
Parameter Word FF hex – ON
Or
Parameter Word 00 hex – OFF
Figure 12 - MDMF Visual Message Waiting Indicator Parameter
5.2.5.6
Mark Bits
Some switching systems are known to insert a string of Mark bits between data bytes under certain
load conditions.
CPE shall tolerate the presence of up to 100 Mark bits, inserted between any two message bytes, with
a maximum of 500 Mark bits per message.
5.2.5.7
Checksum
The Checksum is the last byte of an SDMF/MDMF message. It is used as a simple method for the
detection of single bit errors. The CPE shall calculate the Checksum as the 2’s complement of the
modulo 256 sum of all bytes in the message excluding the checksum byte.
CPE shall tolerate distortions in the Checksum stop bit that may make it appear to be a Space bit
rather than a Mark bit.
5.2.5.8
Markout
CPE FSK reception shall be unaffected by any Markout (a string of Mark bits following the
Checksum word) of up to 4.4 seconds for Type 1 transmission, or 150ms for Type 2 transmission.
The CPE shall ignore any Space bits after the Checksum.
5.2.6
Exception Handling
CPE shall not display an error if it does not recognize the Message Type or a Parameter Type. It shall
count off the number of words given by the Message or Parameter Length and check the subsequent
fields. This allows CPE to gracefully accommodate the deployment of new services.
5.2.6.1
Checksum Error
If the calculated Checksum does not match the received Checksum, the CPE shall either discard the
entire message or provide an indication that the message was received with an error. If CPE supports
the reporting of informative messages for the Checksum error condition, it shall report:

“Error”
or

“Incomplete data”
or

5.2.6.2
“Incomplete”
No Data Detected
If CPE does not detect the presence of the preamble and supports the reporting of an informative
message for this condition, it shall report “No Data”.
5.2.6.3
Out of Range data
When CPE receives data that appears to be out of range but the Checksum is correct, it shall do one
of the following:
24

Display the information as received,
or

Discard the entire message,
or

Manipulate or correct the data received and indicate that a change has occurred.
CPE may convert the case of received ASCII characters (from upper to lower or vice versa). Case
changing is not considered manipulation.
5.3
Physical Line Interface
A Type 1 CPE shall conform to ANSI/TIA/EIA-470-B-1997 On-Hook impedance requirements.
5.3.1
5.3.1.1
FSK Signal Properties
Frequency
The CPE shall accept FSK data with a nominal Space frequency of 2200 Hz and a nominal Mark
frequency of 1200 Hz. In addition, CPE shall tolerate a ± 1 % variation of these nominal values as
follows:

2178 Hz to 2222 Hz for Logical ‘0’ (Space).

1188 Hz to 1212 Hz for Logical ‘1’ (Mark).
5.3.1.2
Signal Levels
For testing purposes, the source impedance of the signal generator shall be 900 ohms. FSK signal
levels are measured with an open circuit termination. The dBm600 levels are then calculated using a
600 Ohm reference termination.
When setting up the signal generator, the signal levels in the test matrix are set with an open circuit
termination. The dBm600 levels are then calculated using a 600 Ohm reference termination. For
example, if a meter were used to measure the signal level on an unterminated line, the level measured
for Mark Signal for Test #1 would be –32 dBm (with the meter set to read dBm600). This would
correspond to a unterminated voltage of 19 mVrms (X dBm600 = 10LOG(V2/600). See ANNEX C
Informative Calculations
5.3.1.3
Type 1 FSK Signal Level Detection Threshold
Type 1 CPE shall detect Mark between –32.2 dBm600 (19 mVrms) and –4.2 dBm600 (476 mVrms)
Type 1 CPE shall detect Space between –36.2 dBm600 (12 mVrms) and –4.2 dBm600 (476 mVrms)
If FSK data is not preceded by power ringing, Type 1 CPE shall reject FSK signals below –48.2
dBm600 (3 mVrms).
If the data is preceded by power ringing, FSK detection may be extended below –48.2 dBm600 (3
mVrms).
5.3.1.4
FSK Twist
The CPE shall accept FSK signals with Twist of the Mark and Space signals, given that the signal
amplitudes are within the specified dynamic range for reception. The twist requirements vary
depending on the signal amplitude to take into account that the amount of twist present will be
associated with the attenuation of the FSK signal. The twist acceptance tables have a larger value of
25
twist for lower FSK signal levels since the attenuation and twist are related to the electrical
characteristics of the loop. The polarity of the Twist may be negative (when the level of Mark is
lower) or positive (when the level of Mark is higher).

Type 1 CPE shall accept FSK signals with twist in the ranges given in the following tables:
Table 3 - Type 1 FSK Positive Twist Acceptance Values
Space Signal
Space Signal
Positive Twist
Level (dBm600)
Level (mVrms)
To Accept
-4.2 dBm600 to –21 dBm600
476 mVrms to 69 mVrms
0 to +6 dB
-21 dBm600 to –26.9 dBm600
69 mVrms to 35 mVrms
0 to +8 dB
-26.9 dBm600 to –36.2 dBm600
35 mVrms to 12 mVrms
0 to +10 dB
Note: When twist tests are performed, it is not required for the CPE to accept FSK signals with the
Mark signal level lower than –32 dBm.
Table 4 - Type 1 FSK Negative Twist Acceptance Values
Mark Signal
Mark Signal
Negative Twist
Level (dBm600)
Level (mVrms)
To Accept
-4.2 dBm600 to -18 dBm600
476 mVrms to 98 mVrms
0 to -3 dB
-18 dBm600 to –32.2 dBm600
98 mVrms to 19 mVrms
0 to -6 dB
5.3.1.5
Baud Rate
The CPE shall accept FSK signals with a nominal symbol rate of 1200 baud, and shall tolerate a ±
1% variation in the symbol rate as follows:

5.3.2
1188 to 1212 baud.
Impairments
5.3.2.1
Single Tone Metallic Noise during FSK
Type 1 devices shall detect on-hook FSK in the presence of single tone metallic noise under the
following conditions:

Mark Level between -26 dBm600 (38 mVrms) and –4.2 dBm600 (476 mVrms).

Space Level between -30 dBm600 (24 mVrms) and –4.2 dBm600 (476 mVrms).
The signal level differential between Mark and Space shall meet the twist requirements as specified
in section 5.3.1.4.
The ratio of the lowest FSK data signal level to single tone metallic noise is greater than or equal to
the minimum SNR values given in Table 5.
For testing purposes, the single frequency noise level shall not exceed the maximum levels given in
Table 5.
The single frequency noise shall be applied and tested using the following test methods:
1. The single frequency noise signal shall be applied during the entire interval from the end of
the first ring, during the FSK data, to the beginning of the second ring.
2. The single frequency noise signal is applied only during the FSK signal.
26
Table 5 - Type 1 Single Tone Noise Requirements
Noise Frequency (f)
Minimum SNR
Maximum Single Frequency
Range
Noise Level
f <= 40 Hz
-24 dB
-6.2 dBm600 (380 mVrms)
40 Hz < f <=80 Hz
-13 dB
-17.2 dBm600 (107 mVrms)
80 Hz < f <= 180 Hz
-9 dB
-21.2 dBm600 (68 mVrms)
180 Hz < f <= 200 Hz
-6 dB
-24.2 dBm600 (48 mVrms)
200 Hz <= f < 3200 Hz
+25 dB
-29.2 dBm600 (27 mVrms)
f > 3200 Hz
+6 dB
-10.2 dBm600 (239 mVrms)
5.3.2.2
Single Tone Metallic Noise before and after FSK
Type 1 CPE shall be capable of receiving FSK data if the FSK data is preceded and / or followed by
a single frequency tone in the range of 200-3200 Hz and not to exceed a maximum level of –6
dBm600.
The tone shall start immediately after power ringing and continue during the data-wait interval until
the start of FSK data, whereupon it shall immediately stop and transition to data. At the end of FSK
data, the data signal shall transition back to the tone for the remainder of the silent interval.
Type 1 devices shall tolerate the presence of the carrier tone during the long silent interval of
subsequent power ringing cycles after FSK data within the same application of ringing.
5.3.2.3
Type 1 - Echo Noise
Signal echo occurs because of mismatches in impedance along the transmission path between the
FSK signal transmitter and the Type 1 CPE. Given that such CPE receive on-hook data in an unterminated line condition, Type 1 CPE should tolerate echo within the FSK signal stream. FSK
signal echo is specified to have up to 2 echoes. The first echo is the round trip echo of the original
FSK signal. The second echo is the round trip echo of the first generation echo.
NOTE - When performing echo noise tests, the second-generation echo should have twice
the attenuation of the first generation echo, and the second-generation echo should have
twice the delay as the first generation echo.
Type 1 CPE should accept FSK data signals that contain signal echoes with a minimum of 13 dB
attenuation for the first generation echo and from 1 to 3.5 ms of delay.
5.3.2.4
Signal Dropouts During Channel Seizure
Impulse noise may cause a short interruption or corruption of the FSK signal. Impulse noise may
cause Dropouts (no data bit received, or incorrect data bit received) in the FSK signal.
Impulse noise shall be simulated by zeroing the data waveform (setting the FSK signal level to 0
volts) for the specified time interval.
Type 1 CPE shall tolerate segmentation of the Channel Seizure Signal caused by impulse noise hits
(dropouts) lasting 10 ms or less, if at least one segment of the Channel Seizure Signal is at least 70
bits long.
Type 1 CPE shall tolerate segmentation in the Channel Seizure Signal caused by up to two
unexpected and contiguous byte values (values other than 0x55) with at least one segment of the
Channel Seizure Signal is at least 70 bits long.
27
5.3.2.5
Immunity To Open Switching Intervals (OSIs) And Line Reversals
An OSI is the temporary removal of DC battery voltage between Tip and Ring for a duration of 10
ms to 350 ms. Two or more OSIs may occur in succession. The interval between two consecutive
OSIs will be at least 100ms.
A Line Reversal is the reversal of the DC polarity between Tip and Ring.
A Line Reversal may occur without an OSI, or immediately before or immediately after an OSI.
5.3.2.6
TYPE 1 OSI and Line Reversal Immunity
Type 1 CPE shall accept Caller-ID messages when OSIs and/or Line Reversals occur during any or
all of the following:

Starting anytime before the first ring.

Starting anytime after the first ring and completing no later than 10 ms before the beginning
of the FSK Channel Seizure.

Starting anytime after the end of the FSK data signal.
5.3.3
Type 1 DC operating Conditions
The CPE shall meet all FSK reception requirements for Type 1 (On-Hook Caller-ID and
VMWI) when the On-Hook DC voltage is between 21 and 80 VDC.
5.3.4
Test Matrix for the FSK Signal Properties, Including Multiple Impairments
The following test matrix may be used to aid in pass and fail determination of the CPE’s FSK
performance. Each test shall be run 10 times. Zero (0) failures on 10 attempts for a given test shall
be considered a pass condition for that test. If a failure occurs in the first 10 attempts, then that test
shall be run 90 more times. If the number of failures does not exceed 1 out of 100, then the pass
condition shall be met for that test.
This test matrix consists of a series of specific test conditions and may be used to define the
perimeter of the multidimensional signal space wherein the CPE shall operate when multiple
impairments exist. This signal space is smaller than the space that would be defined using the
extreme worst case values for each parameter. Although this matrix can be used for testing purposes,
the CPE shall operate everywhere within the signal space enclosed by the perimeter defined in these
test conditions.
The DC line conditions while performing this test shall be 50V +/- 2V
NOTE – When setting up the signal generator, the signal levels in the test matrix are set with
an open circuit termination. The dBm600 levels are then calculated using a 600 Ohm reference
termination. For example, if a meter were used to measure the signal level on an unterminated
line, the level measured for Mark Signal for Test #1 would be –32 dBm (with the meter set to
read dBm600). This would correspond to a unterminated voltage of 19 mVrms (X dBm600 =
2
10LOG(V /600). See ANNEX C Informative Calculations
Test
#
1
Mark
Freq.
Hz
1200
Table 6 - Group A, Variable Level Sensitivity Tests – Type 1
Mark
Space
Space
Baud
Comments
Ampl.
Freq.
Ampl.
Rate
dBm600
Hz
dBm600
-32
2200
-32
1200
Sensitivity test (no Twist)
28
2
3
4
5
6
1200
1200
1200
1200
1200
-32
-4
-28
-20
-12
2200
2200
2200
2200
2200
-36
-4
-28
-20
-12
1200
1200
1200
1200
1200
Sensitivity test (with Twist)
High level input test
Intermediate level test #1
Intermediate level test #2
Intermediate level test #3
Table 7 - Group B, Twist Test - Nominal Otherwise – Types 1
Test
#
Mark
Freq.
Hz
Mark
Ampl.
Space
Freq.
Hz
Space
Ampl.
Baud
Rate
Comments
2200
2200
dBm600
-10
-21
1200
1200
+6 dB Twist, High Level
+6 dB Twist, Low Level
8
1200
1200
dBm600
-4
-15
9
1200
-13
2200
-21
1200
+8 dB Twist, High Level
10
1200
-19
2200
-27
1200
+8 dB Twist, Low Level
11
1200
-17
2200
-27
1200
+10 dB Twist, High Level
12
1200
-26
2200
-36
1200
+10 dB Twist, Low Level
13
1200
-7
2200
-4
1200
-3 dB Twist, High Level
14
1200
-18
2200
-15
1200
-3 dB Twist, Low Level
15
1200
-18
2200
-12
1200
-6 dB Twist, High Level
16
1200
-32
2200
-26
1200
-6 dB Twist, Low Level
7
Table 8 - Group C, Combined Impairments - Frequencies, Baud, and Twist – Type 1
Test
#
Mark
Freq.
Hz
Mark
Ampl.
17
1188
dBm600
-4
18
1188
19
Space
Freq.
Hz
Space
Ampl.
Baud
Rate
2178
dBm600
-4
1188
-4
2222
-4
1188
1212
-4
2178
-4
1188
20
1212
-4
2222
-4
1188
21
1188
-4
2178
-4
1212
22
1188
-4
2222
-4
1212
23
1212
-4
2178
-4
1212
24
1212
-4
2222
-4
1212
29
Comments
0 dB Twist, low Mark,
frequencies and low baud
0 dB Twist, low Mark,
frequencies and low baud
0 dB Twist, high Mark,
frequencies and low baud
0 dB Twist, high Mark,
frequencies and low baud
0 dB Twist, low Mark,
frequencies and high baud
0 dB Twist, low Mark,
frequencies and high baud
0 dB Twist, high Mark,
frequencies and high baud
0 dB Twist, high Mark,
frequencies and high baud
low Space
high Space
low Space
high Space
low Space
high Space
low Space
high Space
25
1188
-10
2178
-13
1188
26
1188
-10
2222
-13
1188
27
1212
-10
2178
-13
1188
28
1212
-10
2222
-13
1188
29
1188
-10
2178
-13
1212
30
1188
-10
2222
-13
1212
31
1212
-10
2178
-13
1212
32
1212
-10
2222
-13
1212
33
1188
-15
2178
-21
1188
34
1188
-15
2222
-21
1188
35
1212
-15
2178
-21
1188
36
1212
-15
2222
-21
1188
37
1188
-15
2178
-21
1212
38
1188
-15
2222
-21
1212
39
1212
-15
2178
-21
1212
40
1212
-15
2222
-21
1212
41
1188
-19
2178
-27
1188
42
1188
-19
2222
-27
1188
43
1212
-19
2178
-27
1188
44
1212
-19
2222
-27
1188
45
1188
-19
2178
-27
1212
46
1188
-19
2222
-27
1212
47
1212
-19
2178
-27
1212
30
+3 dB Twist, low Mark, low
frequencies and low baud
+3 dB Twist, low Mark, high
frequencies and low baud
+3 dB Twist, high Mark, low
frequencies and low baud
+3 dB Twist, high Mark, high
frequencies and low baud
+3 dB Twist, low Mark, low
frequencies and high baud
+3 dB Twist, low Mark, high
frequencies and high baud
+3 dB Twist, high Mark, low
frequencies and high baud
+3 dB Twist, high Mark, high
frequencies and high baud
+6 dB Twist, low Mark, low
frequencies and low baud
+6 dB Twist, low Mark, high
frequencies and low baud
+6 dB Twist, high Mark, low
frequencies and low baud
+6 dB Twist, high Mark, high
frequencies and low baud
+6 dB Twist, low Mark, low
frequencies and high baud
+6 dB Twist, low Mark, high
frequencies and high baud
+6 dB Twist, high Mark, low
frequencies and high baud
+6 dB Twist, high Mark, high
frequencies and high baud
+8 dB Twist, low Mark, low
frequencies and low baud
+8 dB Twist, low Mark, high
frequencies and low baud
+8 dB Twist, high Mark, low
frequencies and low baud
+8 dB Twist, high Mark, high
frequencies and low baud
+8 dB Twist, low Mark, low
frequencies and high baud
+8 dB Twist, low Mark, high
frequencies and high baud
+8 dB Twist, high Mark, low
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
48
1212
-19
2222
-27
1212
49
1188
-26
2178
-36
1188
50
1188
-26
2222
-36
1188
51
1212
-26
2178
-36
1188
52
1212
-26
2222
-36
1188
53
1188
-26
2178
-36
1212
54
1188
-26
2222
-36
1212
55
1212
-26
2178
-36
1212
56
1212
-26
2222
-36
1212
57
1188
-18
2178
-15
1188
58
1188
-18
2222
-15
1188
59
1212
-18
2178
-15
1188
60
1212
-18
2222
-15
1188
61
1188
-18
2178
-15
1212
62
1188
-18
2222
-15
1212
63
1212
-18
2178
-15
1212
64
1212
-18
2222
-15
1212
65
1188
-32
2178
-26
1188
66
1188
-32
2222
-26
1188
67
1212
-32
2178
-26
1188
68
1212
-32
2222
-26
1188
69
1188
-32
2178
-26
1212
31
frequencies and high baud
+8 dB Twist, high Mark, high
frequencies and high baud
+10 dB Twist, low Mark, low
frequencies and low baud
+10 dB Twist, low Mark, high
frequencies and low baud
+10 dB Twist, high Mark, low
frequencies and low baud
+10 dB Twist, high Mark, high
frequencies and low baud
+10 dB Twist, low Mark, low
frequencies and high baud
+10 dB Twist, low Mark, high
frequencies and high baud
+10 dB Twist, high Mark, low
frequencies and high baud
+10 dB Twist, high Mark, high
frequencies and high baud
-3 dB Twist, low Mark, low
frequencies and low baud
-3 dB Twist, low Mark, high
frequencies and low baud
-3 dB Twist, high Mark, low
frequencies and low baud
-3 dB Twist, high Mark, high
frequencies and low baud
-3 dB Twist, low Mark, low
frequencies and high baud
-3 dB Twist, low Mark, high
frequencies and high baud
-3 dB Twist, high Mark, low
frequencies and high baud
-3 dB Twist, high Mark, high
frequencies and high baud
-6 dB Twist, low Mark, low
frequencies and low baud
-6 dB Twist, low Mark, high
frequencies and low baud
-6 dB Twist, high Mark, low
frequencies and low baud
-6 dB Twist, high Mark, high
frequencies and low baud
-6 dB Twist, low Mark, low
frequencies and high baud
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
70
1188
-32
2222
-26
1212
71
1212
-32
2178
-26
1212
72
1212
-32
2222
-26
1212
-6 dB Twist, low Mark, high Space
frequencies and high baud
-6 dB Twist, high Mark, low Space
frequencies and high baud
-6 dB Twist, high Mark, high Space
frequencies and high baud
(Noise applied from end of ring to 200 ms after end of FSK)
Test
#
Mark &
Space
Freq.
& Baud
Rate
Mark &
Space
Ampl.
Noise
Freq.
Hz
dBm600
74
NOM
NOM
-30.2
-30.2
20
40
-6.2
-6.2
-24 dB SNR
-24 dB SNR
75
NOM
-30.2
60
-17.2
-13 dB SNR
76
NOM
-30.2
80
-17.2
-13 dB SNR
77
NOM
-30.2
120
-21.2
-9 dB SNR
78
NOM
-30.2
180
-21.2
-9 dB SNR
79
NOM
-30.2
200
-24.2
-6 dB SNR
80
81
NOM
NOM
-4.2
-4.2
300
700
-29.2
-29.2
+25dB SNR
+25dB SNR
82
NOM
-4.2
1200
-29.2
+25dB SNR
83
NOM
-4.2
1700
-29.2
+25dB SNR
84
NOM
-4.2
2200
-29.2
+25dB SNR
85
NOM
-4.2
2700
-29.2
+25dB SNR
86
NOM
-4.2
3100
-29.2
+25dB SNR
87
NOM
-4.2
3.2K
-10.2
+6 dB SNR
88
NOM
-4.2
4K
-10.2
+6 dB SNR
89
NOM
-4.2
5K
-10.2
+6 dB SNR
90
NOM
-4.2
8K
-10.2
+6 dB SNR
91
NOM
-4.2
10K
-10.2
+6 dB SNR
73
Noise
Ampl.
Comments
dBm600
Table 9 - Group E, Noise Tests – Type 1 (Noise applied during FSK only)
Test
#
Mark &
Space
Freq.
Mark &
Space
Ampl.
Noise
Freq.
Hz
Noise
Ampl.
DBm600
32
Comments
& Baud
Rate
dBm600
93
NOM
NOM
-30.2
-30.2
20
40
-6.2
-6.2
-24 dB SNR
-24 dB SNR
94
NOM
-30.2
60
-17.2
-13 dB SNR
95
NOM
-30.2
80
-17.2
-13 dB SNR
96
NOM
-30.2
120
-21.2
-9 dB SNR
97
NOM
-30.2
180
-21.2
-9 dB SNR
98
NOM
-30.2
200
-24.2
-6 dB SNR
99
100
NOM
NOM
-4.2
-4.2
300
700
-29.2
-29.2
+25dB SNR
+25dB SNR
101
NOM
-4.2
1200
-29.2
+25dB SNR
102
NOM
-4.2
1700
-29.2
+25dB SNR
103
NOM
-4.2
2200
-29.2
+25dB SNR
104
NOM
-4.2
2700
-29.2
+25dB SNR
105
NOM
-4.2
3100
-29.2
+25dB SNR
106
NOM
-4.2
3.2K
-10.2
+6 dB SNR
107
NOM
-4.2
4K
-10.2
+6 dB SNR
108
NOM
-4.2
5K
-10.2
+6 dB SNR
109
NOM
-4.2
8K
-10.2
+6 dB SNR
110
NOM
-4.2
10K
-10.2
+6 dB SNR
92
Table 10 - Group F, Noise Tests – Type 1 with +10 dB FSK Twist
(Noise applied from end of ring to 200 ms after end of FSK)
Test
#
Mark &
Space
Freq.
& Baud
Rate
Mark
Ampl.
Space
Ampl.
dBm600
Noise
Freq.
Hz
dBm600
dBm600
112
NOM
NOM
-20.2
-20.2
-30.2
-30.2
20
40
-6
-6
-24 dB SNR
-24 dB SNR
113
NOM
-20.2
-30.2
60
-17
-13 dB SNR
114
NOM
-20.2
-30.2
80
-17
-13 dB SNR
115
NOM
-20.2
-30.2
120
-21
-9 dB SNR
116
NOM
-20.2
-30.2
180
-21
-9 dB SNR
111
33
Noise
Ampl.
Comments
117
NOM
-20.2
-30.2
200
-24
-6 dB SNR
118
119
NOM
NOM
-4.2
-4.2
-14.2
-14.2
300
700
-39.2
-39.2
+25dB SNR
+25dB SNR
120
NOM
-4.2
-14.2
1200
-39.2
+25dB SNR
121
NOM
-4.2
-14.2
1700
-39.2
+25dB SNR
122
NOM
-4.2
-14.2
2200
-39.2
+25dB SNR
123
NOM
-4.2
-14.2
2700
-39.2
+25dB SNR
124
NOM
-4.2
-14.2
3100
-39.2
+25dB SNR
125
NOM
-4.2
-10.2
3.2K
-16.2
+6 dB SNR
126
NOM
-4.2
-10.2
4K
-16.2
+6 dB SNR
127
NOM
-4.2
-10.2
5K
-16.2
+6 dB SNR
128
NOM
-4.2
-10.2
8K
-16.2
+6 dB SNR
129
NOM
-4.2
-10.2
10K
-16.2
+6 dB SNR
Table 11 - Group G, Noise Tests – Type 1 with –6 dB FSK Twist
(Noise applied from end of ring to 200 ms after end of FSK)
Test
#
Mark &
Space
Freq.
& Baud
Rate
Mark &
Space
Ampl.
dBm600
Noise
Freq.
Hz
dBm600
131
NOM
NOM
-30
-30
-24
-24
20
40
-6
-6
-24 dB SNR
-24 dB SNR
132
NOM
-30
-24
60
-17
-13 dB SNR
133
NOM
-30
-24
80
-17
-13 dB SNR
134
NOM
-30
-24
120
-21
-9 dB SNR
135
NOM
-30
-24
180
-21
-9 dB SNR
136
NOM
-30
-24
200
-24
-6 dB SNR
137
138
NOM
NOM
-10
-10
-4
-4
300
700
-35
-35
+25dB SNR
+25dB SNR
139
NOM
-10
-4
1200
-35
+25dB SNR
140
NOM
-10
-4
1700
-35
+25dB SNR
141
NOM
-10
-4
2200
-35
+25dB SNR
142
NOM
-10
-4
2700
-35
+25dB SNR
143
NOM
-10
-4
3100
-35
+25dB SNR
144
NOM
-10
-4
3.2K
-16
+6 dB SNR
130
Space
Ampl.
Noise
Ampl.
Comments
dBm600
34
145
NOM
-10
-4
4K
-16
+6 dB SNR
146
NOM
-10
-4
5K
-16
+6 dB SNR
147
NOM
-10
-4
8K
-16
+6 dB SNR
148
NOM
-10
-4
10K
-16
+6 dB SNR
Table 12 – Group H, Echo Noise Type 1
Test
#
Mark &
Space
Ampl.
Delay Time
Ms
1st Generation Echo
Level
2nd Generation Echo
Level
dBm600
dBm600
150
dBm600
-16
-16
1.67
2.50
-29
-29
-42
-42
151
-16
3.33
-29
-42
149
Table 13 - Group I, Send without Ringing-Shall Reject Calls – Type 1
Test
#
Mark
Freq.
Hz
152
1200
Mark
Ampl.
dBm600
-49
Space
Freq.
Hz
2200
Space
Ampl.
Baud
Rate
Comments
dBm600
-49
1200
Reject Level
6 TYPE 2 PROTOCOL
6.1
6.1.1
General
Type 2 CPE
Type 2 Customer Premises Equipment (CPE) include all the On-Hook functionality of Type 1, with
the addition of supporting Off-Hook signaling associated with Calling Identity Delivery on Call
Waiting (CIDCW). In the Off-Hook state, a Type 2 CPE shall be capable of detecting a special dual
tone signal known as the CPE Alerting Signal (CAS), completing the handshake sequence preceding
data communication, and decoding data frames packaged in MDMF. In the On-Hook state, Type 2
CPE shall meet all the criteria for Type 1 CPE.
6.2
6.2.1
Functionality
Type 2 Call Waiting Caller ID
Type 2 CPE are required to perform all the Type 1 functions, plus the following eight functions:
1) The CPE shall be able to detect CAS in an On-Hook and Off-Hook state. The detection takes
place in an environment that may contain speech, noise, and other interfering signals.
2) The CPE should be able to detect a non-compatible Off-Hook CPE.
3) The CPE shall be able to mute the Voicepath and send an Acknowledgment Signal (ACK) to
indicate that it received the CAS successfully and is ready to receive data.
35
4) The CPE shall be able to detect and decode the Frequency Shift Keying (FSK) data in both OnHook and Off-Hook states.
NOTE – Shifts in DC voltage (including Open Switching Intervals or line polarity reversals)
may occur before a CAS or after FSK data.
6.2.2
CAS Detection
There are three aspects to defining CAS detection performance: Signal recognition, Talkdown
performance and Talkoff performance.
1) CAS recognition establishes the ability of the CPE to detect the CAS over the range of expected
signal parameters in the absence of speech or noise.
2) CAS talkdown performance establishes the ability of the CAS detector to detect CAS in the
presence of speech, music, and noise. The ability to detect CAS in the presence of interfering
signals is necessary for proper operation with CIDCW. Although the far-end will be muted
during transmission of the CAS, near-end signals may potentially corrupt the CAS and impede its
detection.
3) CAS talkoff performance establishes the ability of the CPE to resist CAS imitations produced by
speech, music, and noise. Distinguishing between legitimate CAS and those simulated by
interfering signals is important for services like CIDCW. Falsely detecting a CAS simulated by
interfering signals will result in undesirable breaks in the Voicepath, which will adversely affect
telephone service quality. Robust CAS performance is necessary because a CAS detector
constantly monitors the line and is exposed to both near-end and far-end signals.
6.2.2.1
CAS Detector Performance Recommendations
The CAS detector performance criteria set forth in this document reference the test plan described in
Telcordia Technologies (formerly Bellcore) documents SR-TSV-002476 and SR-3004. This test
plan attempts to model the real world environment and provides talkoff and talkdown performance
measurements consistent with expected field performance. The test plan makes use of statistical
information gathered from various field studies about the environment in which CAS detectors are
expected to be used. Particularly, the test plan relies upon information about loop loss distribution,
near-end speech level distribution, and far-end speech level distribution. The test plan employs these
distributions to weight CAS detector performance according to the probability that certain
combinations of speech levels and loop losses occur. The weighted performance values are then
calculated as described in Telcordia Technologies SR-TSV-002476 to provide estimates of overall
CAS detector performance. Performance objectives have been established for the average case, the
worst 1% of all combinations and the global case.
Power levels of signals are expressed as power per tone, in dBm referenced to a 600 ohm
termination. Speech levels are expressed as the Active Speech Level (ASL), in dBm, and measured
according to Method B of ITU-T Recommendation P.56. Signal-to-speech power ratios are expressed
in dB, corresponding to the per-tone signal power in dBm minus the active speech level in dBm-ASL.
Talkdown and talkoff testing as described in Telcordia Technologies SR-TSV-002476 uses the 97.6
hour standard speech test library contained in the Telcordia Technologies Licensed Product, LP-B17,
Speech Test CD Set for Type 2 and 3 Customer Premises Equipment.1
1
LP-B17, Speech Test CD Set is a licensed product supplied by Telcordia Technologies (formerly
Bellcore). This information is given for the convenience of users of this Standard and does not
constitute an endorsement by ANSI/TIA of the product named. Equivalent products may be used if
they can be shown to lead to the same results.
36
6.2.2.2
CAS Recognition
The CAS is a dual tone signal nominally 80 ms in duration. Table 14 defines CAS parameter
detection limits. These limits reflect severe combinations of switch, digital loop carrier, and loop
plant variables. Signals outside these limits may be either accepted or rejected by the CAS detector.
6.2.2.2.1
CAS Recognition Parameters
The CPE shall detect CAS satisfying the signal characteristics defined in Table 14, according to the
following rules:
Rule 1: CPE shall detect CAS with any single parameter value between nominal and extreme
value, with all other parameters at their nominal values.
Rule 2: CPE shall also detect CAS when multiple parameters are varied between their
nominal values and 90% of their extreme values.
Table 14 - CAS Parameter Limits
Parameter
Value
Low Tone Frequency
High Tone Frequency
Dynamic Range (dBm per tone)
Power Differential within Dynamic Range (Twist)
Signal Duration
2130 Hz ± 0.5%
2750 Hz ± 0.5%
-14 to -32 dBm
± 6 dB
80 ± 5 ms

Twist is defined as the signal level differential between the lower and upper tones. Twist
may be negative (when the amplitude of the lower frequency tone is lower than the
amplitude of the higher frequency tone) or positive (when the amplitude of the higher
frequency tone is lower than the amplitude of the lower frequency tone). The CPE shall be
capable of detecting CAS with up to ± 6 dB of Twist.

The CPE shall reject all CAS below -45 dBm per tone.

Detection of the CAS by the CPE shall not be impaired by the presence of any normal or
distinctive Subscriber Alerting Signal (SAS). Refer to the Call Waiting (CW) Signal chart in
ANSI T1.401.-1993 for further details on the SAS alert tones.

For testing purposes, the source impedance of the signal generator shall be 900 ohms. CAS
signal levels are measured with a 600 ohm termination in place of the CPE. The 600 ohm
termination is replaced by the CPE before CAS recognition or CAS talkdown testing is
performed.
6.2.2.2.2
CAS Recognition Test Matrix
The test conditions in Table 15, Table 16, Table 17, and Table 18 may be used for CAS recognition
testing with no interfering signals present.
Each test shall be run 100 times. Zero (0) failures on 100 attempts for a given test shall be
considered a pass condition for that test. If a failure occurs in the first 100 attempts, then that test
shall be run 900 more times. If the number of failures does not exceed 1 out of 1000, then the pass
condition shall be met for that test. Tests shall be run at a rate not exceeding 1 test attempt every 2
seconds.
37
Because of the large number of possible tests to show compliance with section 6.2.2.2.1, Table 15,
Table 16, Table 17 and Table 18 are provided to list specific test conditions that may be used to show
compliance.
Table 15 lists the test conditions for all parameters at their nominal values.
Table 16 lists the test conditions for each parameter at its extreme value, with other parameters at
nominal.
Table 17 and Table 18 list test conditions with multiple parameters at 90% of their extreme values.
Table 19 contains a test for the minimum CAS amplitude for which the CPE shall not detect the CAS
.
Table 15 - Group 1, CAS Recognition - All Parameters at Nominal Values
Test
#
Low
Freq.
Tone
Hz
Low
Freq.
Tone
Level
dBm
High
Freq.
Tone
Hz
High
Freq.
Tone
Level
dBm
Twist
Level
dB
CAS
Duration
ms
Comments
1
2130
-22
2750
-22
0
80
All parameters at nominal
Table 16 - Group 2, CAS Recognition - One Parameter at a Time at the Extreme Value
Test
#
Low
Freq.
Tone
Hz
Low
Freq.
Tone
Level
dBm
High
Freq.
Tone
Hz
2
3
4
5
2119.3
2140.7
2130
2130
-22
-22
-22
-22
2750
2750
2736.2
2763.8
High
Freq.
Tone
Level
dBm
Twist
Level
dB
CAS
Duration
ms
Comments
Tone Frequency Limit Tests
-22
-22
-22
-22
0
0
0
0
80
80
80
80
Low Tone at Low Freq Limit
Low Tone at High Freq Limit
High Tone at Low Freq Limit
High Tone at High Freq Limit
Dynamic Range Tests
6
7
2130
2130
-32
-14
2750
2750
-32
-14
0
0
80
80
Both Tones at minimum levels
Both Tones at maximum levels
Power Differential (Twist) Tests
8
9
10
11
2130
2130
2130
2130
-32
-26
-14
-20
2750
2750
2750
2750
-26
-32
-20
-14
-6
+6
+6
-6
80
80
80
80
Negative Twist
Positive Twist
Positive Twist
Negative Twist
Signal Duration Tests
12
13
2130
2130
-22
-22
2750
2750
-22
-22
0
0
75
85
38
Minimum CAS duration
Maximum CAS duration
Table 17 - Group 3, CAS Recognition - Parameters at 90% from Nominal, 75.5 ms CAS
Test
#
Low
Freq.
Tone
Hz
Low
Freq.
Tone
Level
dBm
14
15
16
17
2120.4
2120.4
2139.6
2139.6
-31
-31
-31
-31
High
Freq.
Tone
Hz
High
Freq.
Tone
Level
dBm
Twist
Level
dB
CAS
Comments
Duration LF1= Low Tone Lower Freq. limit
LF2= High Tone Lower Freq. limit
ms
UF1= Low Tone Upper Freq. limit
UF2= High Tone Upper Freq. Limit
Both tones at 90% of nominal frequencies, low amplitude, no Twist
2737.6
2762.4
2737.6
2762.4
-31
-31
-31
-31
0
0
0
0
75.5
75.5
75.5
75.5
LF1, LF2
LF1, UF2
UF1, LF2
UF1, UF2
Both tones at 90% of nominal frequencies, high amplitude, no Twist
18
19
20
21
2120.4
2120.4
2139.6
2139.6
-14.8
-14.8
-14.8
-14.8
2737.6
2762.4
2737.6
2762.4
-14.8
-14.8
-14.8
-14.8
0
0
0
0
75.5
75.5
75.5
75.5
LF1, LF2
LF1, UF2
UF1, LF2
UF1, UF2
Both tones at 90% of nominal frequencies, low amplitude, negative Twist at 90%
22
23
24
25
2120.4
2120.4
2139.6
2139.6
26
27
28
29
2120.4
2120.4
2139.6
2139.6
-31
-31
-31
-31
2737.6
2762.4
2737.6
2762.4
-25.6
-25.6
-25.6
-25.6
-5.4
-5.4
-5.4
-5.4
75.5
75.5
75.5
75.5
LF1, LF2
LF1, UF2
UF1, LF2
UF1, UF2
Both tones at 90% of nominal frequencies, low amplitude, positive Twist at 90%
-25.6
-25.6
-25.6
-25.6
2737.6
2762.4
2737.6
2762.4
-31
-31
-31
-31
+5.4
+5.4
+5.4
+5.4
75.5
75.5
75.5
75.5
LF1, LF2
LF1, UF2
UF1, LF2
UF1, UF2
Both tones at 90% of nominal frequencies, high amplitude, positive Twist at 90%
30
31
32
33
2120.4
2120.4
2139.6
2139.6
34
35
36
37
2120.4
2120.4
2139.6
2139.6
-14.8
-14.8
-14.8
-14.8
2737.6
2762.4
2737.6
2762.4
-20.2
-20.2
-20.2
-20.2
+5.4
+5.4
+5.4
+5.4
75.5
75.5
75.5
75.5
LF1, LF2
LF1, UF2
UF1, LF2
UF1, UF2
Both tones at 90% of nominal frequencies, high amplitude, negative Twist at 90%
-20.2
-20.2
-20.2
-20.2
2737.6
2762.4
2737.6
2762.4
-14.8
-14.8
-14.8
-14.8
-5.4
-5.4
-5.4
-5.4
75.5
75.5
75.5
75.5
39
LF1, LF2
LF1, UF2
UF1, LF2
UF1, UF2
Table 18 - Group 3, CAS Recognition - Parameters at 90% from Nominal, 84.5 ms CAS
Test
#
Low
Freq.
Tone
Hz
Low
Freq.
Tone
Level
dBm
38
39
40
41
2120.4
2120.4
2139.6
2139.6
-31
-31
-31
-31
High
Freq.
Tone
Hz
High
Freq.
Tone
Level
dBm
Twist
Level
dB
CAS
Comments
Duration LF1= Low Tone Lower Freq. limit
LF2= High Tone Lower Freq. limit
ms
UF1= Low Tone Upper Freq. limit
UF2= High Tone Upper Freq. Limit
Both tones at 90% of nominal frequencies, low amplitude, no Twist
2737.6
2762.4
2737.6
2762.4
-31
-31
-31
-31
0
0
0
0
84.5
84.5
84.5
84.5
LF1, LF2
LF1, UF2
UF1, LF2
UF1, UF2
Both tones at 90% of nominal frequencies, high amplitude, no Twist
42
43
44
45
2120.4
2120.4
2139.6
2139.6
-14.8
-14.8
-14.8
-14.8
2737.6
2762.4
2737.6
2762.4
-14.8
-14.8
-14.8
-14.8
0
0
0
0
84.5
84.5
84.5
84.5
LF1, LF2
LF1, UF2
UF1, LF2
UF1, UF2
Both tones at 90% of nominal frequencies, low amplitude, negative Twist at 90%
46
47
48
49
2120.4
2120.4
2139.6
2139.6
50
51
52
53
2120.4
2120.4
2139.6
2139.6
-31
-31
-31
-31
2737.6
2762.4
2737.6
2762.4
-25.6
-25.6
-25.6
-25.6
-5.4
-5.4
-5.4
-5.4
84.5
84.5
84.5
84.5
LF1, LF2
LF1, UF2
UF1, LF2
UF1, UF2
Both tones at 90% of nominal frequencies, low amplitude, positive Twist at 90%
-25.6
-25.6
-25.6
-25.6
2737.6
2762.4
2737.6
2762.4
-31
-31
-31
-31
+5.4
+5.4
+5.4
+5.4
84.5
84.5
84.5
84.5
LF1, LF2
LF1, UF2
UF1, LF2
UF1, UF2
Both tones at 90% of nominal frequencies, high amplitude, positive Twist at 90%
54
55
56
57
2120.4
2120.4
2139.6
2139.6
58
59
60
61
2120.4
2120.4
2139.6
2139.6
-14.8
-14.8
-14.8
-14.8
2737.6
2762.4
2737.6
2762.4
-20.2
-20.2
-20.2
-20.2
+5.4
+5.4
+5.4
+5.4
84.5
84.5
84.5
84.5
LF1, LF2
LF1, UF2
UF1, LF2
UF1, UF2
Both tones at 90% of nominal frequencies, high amplitude, negative Twist at 90%
-20.2
-20.2
-20.2
-20.2
2737.6
2762.4
2737.6
2762.4
-14.8
-14.8
-14.8
-14.8
-5.4
-5.4
-5.4
-5.4
84.5
84.5
84.5
84.5
LF1, LF2
LF1, UF2
UF1, LF2
UF1, UF2
Table 19 - Group 4, CAS Reject Amplitude
Test
#
Low
Freq.
Tone
Hz
Low
Freq.
Tone
Level dBm
High
Freq.
Tone
Hz
High
Freq.
Tone
Level dBm
Twist
Level
dB
40
CAS
Duration
ms
Comments
62
2130
6.2.2.3
-46
2750
-46
0
80
Both Tones below -45 dBm
Talkdown Performance Parameters
A CAS talkdown is defined as the failure to detect a CAS in the presence of speech, music, or noise
and respond with an ACK Signal within 100 ms after the end of the CAS.
Three key criteria were determined to be important for measuring CAS talkdown performance. The
first criterion sets a talkdown performance objective for the case of an average near-end speech level
on a loop with average loss. The second criterion sets a weighted-average talkdown performance
objective for the worst 1% of combinations representing loud near-end speech levels with high loss
loops. The third criterion sets a global weighted-average talkdown performance objective for all
combinations of near-end speech levels and loop losses. These three criteria provide an overall
global talkdown performance measure tempered with the talkdown performance with average signal
levels, and a measure of the worst talkdown performance that may occur.
Talkdown performance measurement introduces the concept of a Modified Signal Recognition
Percentage (MSRP) to account for the alternation of speakers during a typical telephone
conversation. When testing talkdown performance, every CAS that is sent is theoretically
accompanied by near-end speech. In reality, it is rare that the near-end talker will occupy the talk
path 100% of the call time. It is more realistic to assume, as the test plan does, that on average both
the near-end and far-end talkers speak approximately 50% of the call time, with few instances of
double talk. The implication of such an assumption on CAS detector talkdown performance is that
approximately 50% of the CAS will be received while the near-end is in the listening mode (i.e. the
far-end is talking). CAS received while the near-end is in the listening mode will not be corrupted by
speech and will most likely be detected if the CAS detector meets the CAS recognition
recommendations in section 6.2.2.2.1. The test plan accounts for this assumption by modifying the
actual talkdown performance data to obtain what is known as the Modified Signal Recognition
Percentage:

MSRP = 0.5*(100% + Actual Signal Recognition Percentage(%))
The MSRP essentially provides a 50% credit in talkdown performance for all CAS detectors,
assuming that the CAS recognition tests in section 6.2.2.2.1 are all passed. In essence, the worst
MSRP that a CAS detector can have is 50%.CPE shall meet the following criteria for talkdown
performance.
1) The Modified Signal Recognition Percentage under conditions of an average CAS level (-22
dBm/tone) and an average near-end speech level (-19dBm-ASL) is to be at least 99.5%.
2) The weighted-average of the Modified Signal Recognition Percentages measured under the
conditions specified by the worst one percent of the 72 combinations is to be at least 93.0%.
3) The global, weighted-average of the Modified Signal Recognition Percentages measured under
the conditions specified by all 72 combinations is to be at least 99.5%.
NOTE - See Appendices A and B in Telcordia Technologies SR-TSV-002476 for more
details.
6.2.2.4
Talkoff Performance Parameters
A CAS detector talkoff is a CPE CAS detection caused by speech, music, or noise that triggers the
sending of an ACK Signal.
Three key criteria were determined to be important for measuring CAS talkoff performance. The
first criterion sets a talkoff performance objective for the case of a near-end talker with an average
41
speech level and a far-end talker with an average speech level. The second criterion sets a weightedaverage talkoff performance objective for the worst 1% of combinations representing loud near-end
talkers speaking to loud far-end talkers. The third criterion sets a global, weighted-average talkoff
performance objective on all combinations of near-end talkers and far-end talkers. These three
criteria provide an overall global talkoff performance measure tempered with the talkoff performance
with average speech levels, and the worst talkoff performance that may occur.
CPE shall meet the following criteria for talkoff performance.
1) Under conditions of an average near-end speech level (-19 dBm-ASL) and an average far-end
speech level (-28 dBm-ASL), the Combined Talkoff Rate is to be less than 0.0222 talkoffs/hour
or less than 1 talkoff in 45 hours.
2) The weighted-average of the Combined Talkoff Rates for the worst one percent of the 63
combinations of near-end and far-end speech levels is to be less than 0.1000 talkoffs/hour or less
than 1 talkoff in 10 hours.
3) The global weighted-average of the Combined Talkoff Rates for all 63 combinations of near-end
and far-end speech levels is to be less than 0.0286 talkoffs/hour or less than 1 talkoff in 35 hours.
NOTE - See Appendices A and B in Telcordia Technologies SR-TSV-002476 for more
details.
The Combined Talkoff Rate (CTR) mentioned in the three talkoff performance objectives represents
the sum of one half the talkoff rate measured for the near-end speech level plus one half the talkoff
rate measured for the far-end speech level.

CTR = 0.5*(near-end talkoff rate + far-end talkoff rate)
The CTR is the average talkoff rate for a given pair of near-end and far-end speech levels based on
the assumption that each party speaks 50% of the call time.
See Appendices A and B in Telcordia Technologies SR-TSV-002476 for more information on
talkoff testing.
6.2.2.5
CAS Check Muting
A CAS Check Mute is the muting of the near-end audio path for purposes of CAS detection. A mute
condition in this case is defined to be any loss of more than 3 dB inserted in the path between the
transmitter to Tip and Ring, or Tip and Ring to the receiver. This detection technique monitors Tip
and Ring for CAS, when a signal that matches the template for CAS occurs, near-end audio is muted.
This allows the CAS detector to continue to monitor the far-end (source of CAS) without interfering
speech, thereby allowing for more robust detection of CAS. Muting of the near-end audio path has
the potential to cause annoying audible clicks or pops, hence the need for limits on duration and rate
of CAS Check Mutes that do not result in a valid CAS detection.
CPE implementing a CAS detection algorithm employing CAS Check Muting shall meet the
following performance criteria:
1. Mute Duration: less than or equal to 50 milliseconds.
2. Mute Talkoff Rate: for all 63 combinations of near-end and far-end speech levels the CPE shall
average less than 2 mutes/hour or no more than 20 in 10 hours.
3. No single hour shall have more than four CAS Check Mutes.
4. CAS Check Muting shall not introduce additional signals on Tip and Ring or the receiver with an
instantaneous amplitude more than 6dB above the peaks of the -22dBm CAS test tone.
42
NOTE - It is the responsibility of the manufacturer to show that the CPE will meet the
above requirements by offering a method to disable the feature or a suitable test method to
show compliance.
6.2.3
CAS-ACK Handshake
Switching systems alert CPE with a CAS prior to attempting transmission of calling line identity
information for a waiting call. Upon detection of CAS, Type 2 CPE shall mute its Voicepath. While
the Voicepath is muted, no signals unrelated to the CAS-ACK handshake shall be transmitted onto
Tip & Ring by the CPE. Type 2 CPE should perform an extension check to determine if any other
CPE are off-hook during the CAS-ACK handshake. If no extension is in use, the CPE shall respond
to the switch with an ACK to indicate that the CPE is prepared to receive the FSK data. After the
conclusion of FSK data reception, the CPE shall re-establish its Voicepath. If the CPE does not
perform an extension in use check it shall always respond with an ACK which conforms to the
timing shown below.
6.2.3.1
Line and CPE States
The CPE uses information about the condition of the Tip & Ring interface referred to as the Line
State, and information about it’s hook status known as the CPE State.
The Line State can be one of two conditions: In-Use, or High.

For test purposes the Line State shall be considered In-Use when the voltage on the Tip & Ring
interface is 15 volts or below.

For test purposes the Line State shall be considered High when the voltage on the Tip & Ring
interface is above 17 volts.
Note – Due to the transient nature of the momentary on-hook state of an EIU check these voltages are
lower than those specified for steady state on-hook voltage. These thresholds reduce the false
detection of an off-hook extension telephone.
These voltages are used for test purposes and are based on steady state idle line network voltages that
typically range from 42 to 80 volts. CPE manufacturers however should recognize that idle line
network voltages may range from 21 to 80 volts, and that CPE should function correctly over this
range. In some cases the idle line voltage may be less than 21 volts. Reference should be made to
ANSI – T1.401.-1993 and ANSI/TIA/EIA-470-B-1997.
The CPE State can have one of three conditions: On-Hook or Off-Hook as defined in
ANSI/TIA/EIA-470-B-1997 and a Momentary On-Hook state in which the CPE resistance is 50k
ohms or greater. For the purpose of testing, an adjunct with its attached telephone terminal is
considered as one CPE.
6.2.3.2
CAS-ACK Handshake Protocol
Three key factors influence the timing of the CAS-ACK handshake protocol. First, the CAS-ACK
handshake must be consistent with timing parameters expected by the network. This requires that the
transmission of the ACK begin no later than 100 ms after the end of CAS as measured on the Tip &
Ring interface. Second, the CPE may perform a check to determine if another CPE is Off-Hook. If
such equipment is detected, the CAS-ACK handshake is aborted to prevent annoying a user with a
data signal and potentially causing unreliable service. Third, the timing of the CAS-ACK handshake
protocol must provide allowances for variation in CPE CAS detection delay, CAS extension by
speech, CAS shortening by speech, and practical tolerances in switching the DC line termination.
The following rules shall govern the timing structure of the CAS-ACK handshake when performing a
Extension in Use Check and are measured without speech on the line:
43
1) Each Off-Hook CPE shall proceed to the Momentary On-Hook state not earlier than 25 ms
and no later than 45 ms after the end of CAS as measured on the Tip & Ring interface.
NOTE - The 25 ms delay is necessary to prevent the On-Hook transition from corrupting the
CAS for other CPE that may have not completely qualified the signal. The additional 20 ms
that defines the 45 ms upper limit allows for variation in CAS detection delay.
2) After detecting a Line High state, the CPE shall go Off-Hook. The CPE shall allow the line
to remain in the High state for at least 5 ms but not more than 8 ms. If no Line High state is
detected within 40 ms after going On-Hook, the CPE shall return to the Off-Hook state.
3) After going Off-Hook the CPE shall begin transmission of the ACK no earlier than 30 ms
and no later than 40 ms after the leading edge of the Line High voltage transition.
4) All CPE, regardless of their prior CPE State, shall be ready to receive the start of FSK data
30 ms after the end of the ACK tone. All CPE shall return to their previous state and be
ready to receive CAS (On-Hook or Off-Hook) within 50 ms after the end of reception of
data.
5) If data transmission does not begin within 500 ms from the end of the ACK then all CPE
shall return to their previous state and be ready to receive CAS within 50 ms.
6) All CPE shall monitor the line while On-Hook or Off-Hook to receive Caller-ID messages to
maintain a consistent call log.
As indicated in Figure 13, the CAS-ACK handshake protocol allows for up to 35 ms of CAS
detection delay and signal extension after the true end of CAS. It also allows for up to 25 ms of
signal shortening. The ACK delay has taken into account practical tolerances on switching the DC
line termination.
44
Mute the talking and listening
paths. No signals unrelated to
the CAS-ACK handshake shall
be transmitted.
All CPE return to their previous
state and re-establish the
talking and listening paths
< 50 ms
< 100 ms
CAS
ACK
25 ms – 45 ms
FSK Data
30 ms – 40 ms
85 ms – 605 ms
(See Note 1)
(See Note 2)
5 ms – 8 ms
CPE monitors line for linehigh status
CPE goes on-hook after
detecting CAS and begins
monitoring line status
5 ms – 40 ms
CPE returns Off-Hook and
begins transmission of the
ACK signal.
Line State
CPE shall allow the line to remain in
the high state for at least 5 mS but
not more than 8 mS. CPE shall return
off-hook within 40mS.
CPE State
1. It is desirable to have the Line High signal begin as soon as possible in this period
2. If no data is received within 605ms then all CPE shall return to their previous state within
50ms
Figure 13 – CAS-ACK Handshake Diagram
In the event that the CPE does not perform and Extension in Use Check the following rules shall
govern the timing structure of the CAS-ACK handshake and are measured without speech on the
line:
1) After detection of the CAS the CPE shall begin transmission of the ACK no earlier than
55ms and no later than 85 ms after the end of the CAS tone as measured on Tip and Ring.
2) All CPE shall be ready to receive the start of FSK data 30 ms after the end of the ACK tone.
All CPE shall be ready to receive CAS (On-Hook or Off-Hook) within 50 ms after the end of
reception of data.
3) If data transmission does not begin within 500 ms from the end of the ACK, then all CPE
shall return to their previous state and be ready to receive CAS within 50 ms.
4) All CPE shall monitor the line while On-Hook or Off-Hook to receive Caller-ID messages to
maintain a consistent call log.
45
6.2.3.3
ACK Signal Generation
The ACK Signal is a dual tone signal, commonly referred to as DTMF D. The network requires that
the CPE begins to transmit the ACK Signal within 100ms after the end of CAS transmission. All
DTMF transmission characteristics shall meet the requirements of ANSI/TIA/EIA-470-B-1997
including test variations in DC loop characteristics.
NOTE – If the switch does not receive the ACK Signal within the required time limits,
a time out occurs, the DTMF receiver is disconnected, and the far-end is
reconnected. Refer to Telcordia Technologies GR-30-CORE.
6.2.3.4
Voicepath Mute Control
CPE shall mute its Listening and Talking-Paths and disable the DTMF keypad no earlier than 25 ms
and no later than 60 ms after the end of CAS as measured on the Tip & Ring interface without
speech.
CPE shall provide at least 50 dB of attenuation between the line and its Talking and Listening-Paths
across the frequency band of 200 to 3200 Hz.
CPE shall restore the Voicepath and enable the DTMF keypad within 50 ms after the end of the FSK
signal. The CPE shall interpret the end of the FSK signal as any of the following:
1) Absence of carrier signals on the line between 200-3200 Hz. Signals below –68 dBm shall be
interpreted as absence of carrier. Signals between –36 dBm and -68 dBm may be interpreted as
absence of carrier.
2) More than 5 framing errors in the FSK message.
3) More than 150 ms of continuous Mark or Space signal at –36 dBm or higher.
The CPE shall stay in the muted state regardless of the data bytes decoded until one of the
conditions stated above is met (i.e. the CPE shall not simply un-mute after the Checksum).
NOTE – This functionality should allow the CPE to stay muted during an actual FSK
transmission (i.e. for caller-ID or an ADSI message), but the CPE will not stay muted
if the FSK carrier detected is due to speech or noise.
NOTE – It is desired that the mute duration following the FSK be as short as
possible for systems unable to meet the 50ms un-mute time requirement due to the
use of a secondary transmission system from the FSK demodulator to a remote
device (e.g. a cordless phone).
6.3
Type 2 Mark Signal
Type 2 and 2.5 CPE shall accept CIDCW messages that are preceded by a Mark Signal (normally a
block of 80 bits of Mark) whose contiguous length is between:

6.4
50 and 110 bits.
Physical Line Interface
A Type 2 CPE shall conform to ANSI/TIA/EIA-470-B-1997 On-Hook impedance and Off-Hook
resistance requirements.
6.4.1
6.4.1.1
FSK Signal Properties
Frequency
The CPE shall accept FSK data with a nominal Space frequency of 2200 Hz and a nominal Mark
frequency of 1200 Hz. In addition, CPE shall tolerate a ± 1 % variation of these nominal values as
follows:
46

2178 Hz to 2222 Hz for Logical ‘0’ (Space).

1188 Hz to 1212 Hz for Logical ‘1’ (Mark).
6.4.1.2
Type 2 FSK Signal Level Detection Threshold
For testing purposes, the source impedance of the signal generator shall be 900 ohms. FSK signal
levels are measured with a 600-ohm termination in place of the CPE. The 600 ohm termination is
replaced by the CPE before testing is performed.
Type 2 CPE shall detect Mark between –32 dBm600 (19 mVrms) and –4.2 dBm600 (476 mVrms)
Type 2 CPE shall detect Space between –36 dBm600 (12 mVrms) and –4.2 dBm600 (476 mVrms)
6.4.1.3
FSK Twist
The CPE shall accept FSK signals with Twist of the Mark and Space signals, given that the signal
amplitudes are within the specified dynamic range for reception, The twist requirements vary
depending on the signal amplitude to take into account that the amount of twist present will be
associated with the attenuation of the FSK signal. The polarity of the Twist may be negative (when
the level of Mark is lower) or positive (when the level of Mark is higher).

Type 1 CPE shall accept FSK signals with twist in the ranges given in the following tables:
Table 20 - Type 2 FSK Positive Twist Acceptance Values
Space Signal
Space Signal
Positive Twist
Level (dBm)
Level (mVrms)
To Accept
-12 dBm600 to -25 dBm600
195 mVrms to 27 mVrms
0 to +6 dB
-25 dBm600 to -29 dBm600
43 mVrms to 27 mVrms
0 to +8 dB
-29 dBm600 to -36 dBm600
27 mVrms to 12 mVrms
0 to +10 dB
Note: When twist tests are performed, it is not required for the CPE to accept FSK signals with the
Mark signal level lower than –32 dBm.
Table 21 - Type 2 FSK Negative Twist Acceptance Values
Mark Signal
Mark Signal
Negative Twist
Level (dBm)
Level (mVrms)
To Accept
-12 dBm600 to -22 dBm600
195 mVrms to 61 mVrms
0 to -3 dB
-22 dBm600 to -32 dBm600
61 mVrms to 19 mVrms
0 to -6 dB
6.4.1.4
Baud Rate
The CPE shall accept FSK signals with a nominal symbol rate of 1200 baud, and shall tolerate a ±
1% variation in the symbol rate as follows:

6.4.2
1188 to 1212 baud.
Impairments
6.4.2.1
Single Tone Metallic Noise
Type 1 devices shall detect on-hook FSK in the presence of single tone metallic noise under the
following conditions:

Mark Level between -26 dBm600 (38 mVrms) and –12 dBm600 (195 mVrms).
47

Space Level between -30 dBm600 (24 Vrms) and –12 dBm600 (195 mVrms).
The signal level differential between Mark and Space shall meet the twist requirements as specified
in section 6.4.1.3
The ratio of the lowest FSK data signal level to single tone metallic noise is greater than or equal to
the minimum SNR values given in Table 5.
For testing purposes, the single frequency noise level shall not exceed the maximum levels given in
Table 5.
The single frequency noise shall be applied and tested using the following test methods:
1. The single frequency noise signal shall be applied during the entire interval from the end of
the first ring, during the FSK data, to the beginning of the second ring.
2. The single frequency noise signal is applied only during the FSK signal.
Table 22 - Type 2 Single Tone Noise Requirements
Noise Frequency (f)
Minimum SNR
Maximum Single Frequency
Range
Noise Level
f <= 40 Hz
-24 dB
-6.2 dBm600 (380 mVrms)
40 Hz < f <=80 Hz
-13 dB
-17.2 dBm600 (107 mVrms)
80 Hz < f <= 180 Hz
-9 dB
-21.2 dBm600 (68 mVrms)
180 Hz < f <= 200 Hz
-6 dB
-24.2 dBm600 (48 mVrms)
200 Hz <= f < 3200 Hz
+25 dB
-37.2 dBm600 (10 mVrms)
f > 3200 Hz
+6 dB
-18.2 dBm600 (95 mVrms)
6.4.2.2
Immunity To Open Switching Intervals (OSIs) And Line Reversals
An OSI is the temporary removal of DC battery voltage between Tip and Ring for a duration of 10
ms to 350 ms. Two or more OSIs may occur in succession. The interval between two consecutive
OSIs will be at least 100ms.
A Line Reversal is the reversal of the DC polarity between Tip and Ring.
A Line Reversal may occur without an OSI, or immediately before or immediately after an OSI.
6.4.2.3
TYPE 2 OSI and Line Reversal Immunity
Type 2 CPE shall receive CAS and accept Caller-ID messages when OSIs and/or Line Reversals
occur during any or all of the following:

Starting anytime before the SAS and completing no later than 10 ms before the beginning of
the SAS.

Starting anytime before the CAS and completing no later than 10 ms before the beginning of
the CAS.

Starting anytime after the end of the Acknowledgment signal and completing no later than 10
ms before the beginning of the FSK Mark Signal.

Starting anytime after the end of the FSK data signal.
6.4.3
TYPE 2 DC Operating Range
The CPE shall meet all FSK reception requirements for Type 2 (Off-Hook Caller-ID) when the
Off-Hook current is from 18 mA to 80 mA.
48
6.4.4
Test Matrix for the FSK Signal Properties, Including Multiple Impairments
The following test matrix may be used to aid in pass and fail determination of the CPE’s FSK
performance. Each test shall be run 10 times. Zero (0) failures on 10 attempts for a given test shall
be considered a pass condition for that test. If a failure occurs in the first 10 attempts, then that test
shall be run 90 more times. If the number of failures does not exceed 1 out of 100, then the pass
condition shall be met for that test.
This test matrix consists of a series of specific test conditions and may be used to define the
perimeter of the multidimensional signal space wherein the CPE shall operate when multiple
impairments exist. This signal space is smaller than the space that would be defined using the
extreme worst case values for each parameter. Although this matrix can be used for testing purposes,
the CPE shall operate everywhere within the signal space enclosed by the perimeter defined in these
test conditions.
The DC line conditions while performing this test shall be 40mA +/- 2mA
NOTE – When setting up the signal generator, the signal levels in The Type 2 FSK Test Tables are
set with a 600 Ohm termination. When the tests are performed, the 600 Ohm termination is removed
and the CPE is connected in the Off-Hook state.
Test
#
1
2
3
4
5
6
Table 23 - Group A, Variable Level Sensitivity Tests – Type 2
Mark
Mark
Space
Space
Baud
Comments
Freq.
Ampl.
Freq.
Ampl.
Rate
Hz
dBm600
Hz
dBm600
1200
-32
2200
-32
1200
Sensitivity test (no Twist)
1200
-32
2200
-36
1200
Sensitivity test (with Twist)
1200
-12
2200
-12
1200
High level input test
1200
-30
2200
-30
1200
Intermediate level test #1
1200
-24
2200
-24
1200
Intermediate level test #2
1200
-18
2200
-18
1200
Intermediate level test #3
Table 24 - Group B, Twist Test - Nominal Otherwise – Type 2
Test
#
Mark
Freq.
Hz
Mark
Ampl.
7
8
1200
1200
dBm600
-12
-19
9
1200
10
Space
Freq.
Hz
Space
Ampl.
Baud
Rate
Comments
2200
2200
dBm600
-18
-25
1200
1200
+6 dB Twist, High Level
+6 dB Twist, Low Level
-17
2200
-25
1200
+8 dB Twist, High Level
1200
-21
2200
-29
1200
+8 dB Twist, Low Level
11
1200
-19
2200
-29
1200
+10 dB Twist, High Level
12
1200
-26
2200
-36
1200
+10 dB Twist, Low Level
13
1200
-15
2200
-12
1200
-3 dB Twist, High Level
14
1200
-22
2200
-19
1200
-3 dB Twist, Low Level
15
1200
-22
2200
-16
1200
-6 dB Twist, High Level
49
16
1200
-32
2200
-26
1200
Test
#
Mark
Freq.
Hz
Mark
Ampl.
Space
Freq.
Hz
Space
Ampl.
Baud
Rate
2178
dBm600
-12
1188
17
1188
dBm600
-12
18
1188
-12
2222
-12
1188
19
1212
-12
2178
-12
1188
20
1212
-12
2222
-12
1188
21
1188
-12
2178
-12
1212
22
1188
-12
2222
-12
1212
23
1212
-12
2178
-12
1212
24
1212
-12
2222
-12
1212
25
1188
-14
2178
-17
1188
26
1188
-14
2222
-17
1188
27
1212
-14
2178
-17
1188
28
1212
-14
2222
-17
1188
29
1188
-14
2178
-17
1212
30
1188
-14
2222
-17
1212
31
1212
-14
2178
-17
1212
32
1212
-14
2222
-17
1212
50
-6 dB Twist, Low Level
Comments
0 dB Twist, low Mark, low
frequencies and low baud
0 dB Twist, low Mark, high
frequencies and low baud
0 dB Twist, high Mark, low
frequencies and low baud
0 dB Twist, high Mark, high
frequencies and low baud
0 dB Twist, low Mark, low
frequencies and high baud
0 dB Twist, low Mark, high
frequencies and high baud
0 dB Twist, high Mark, low
frequencies and high baud
0 dB Twist, high Mark, high
frequencies and high baud
+3 dB Twist, low Mark, low
frequencies and low baud
+3 dB Twist, low Mark, high
frequencies and low baud
+3 dB Twist, high Mark, low
frequencies and low baud
+3 dB Twist, high Mark, high
frequencies and low baud
+3 dB Twist, low Mark, low
frequencies and high baud
+3 dB Twist, low Mark, high
frequencies and high baud
+3 dB Twist, high Mark, low
frequencies and high baud
+3 dB Twist, high Mark, high
frequencies and high baud
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
33
1188
-19
2178
-25
1188
34
1188
-19
2222
-25
1188
35
1212
-19
2178
-25
1188
36
1212
-19
2222
-25
1188
37
1188
-19
2178
-25
1212
38
1188
-19
2222
-25
1212
39
1212
-19
2178
-25
1212
40
1212
-19
2222
-25
1212
41
1188
-23
2178
-31
1188
42
1188
-23
2222
-31
1188
43
1212
-23
2178
-31
1188
44
1212
-23
2222
-31
1188
45
1188
-23
2178
-31
1212
46
1188
-23
2222
-31
1212
47
1212
-23
2178
-31
1212
48
1212
-23
2222
-31
1212
49
1188
-26
2178
-36
1188
50
1188
-26
2222
-36
1188
51
1212
-26
2178
-36
1188
52
1212
-26
2222
-36
1188
53
1188
-26
2178
-36
1212
54
1188
-26
2222
-36
1212
55
1212
-26
2178
-36
1212
51
+6 dB Twist, low Mark, low
frequencies and low baud
+6 dB Twist, low Mark, high
frequencies and low baud
+6 dB Twist, high Mark, low
frequencies and low baud
+6 dB Twist, high Mark, high
frequencies and low baud
+6 dB Twist, low Mark, low
frequencies and high baud
+6 dB Twist, low Mark, high
frequencies and high baud
+6 dB Twist, high Mark, low
frequencies and high baud
+6 dB Twist, high Mark, high
frequencies and high baud
+8 dB Twist, low Mark, low
frequencies and low baud
+8 dB Twist, low Mark, high
frequencies and low baud
+8 dB Twist, high Mark, low
frequencies and low baud
+8 dB Twist, high Mark, high
frequencies and low baud
+8 dB Twist, low Mark, low
frequencies and high baud
+8 dB Twist, low Mark, high
frequencies and high baud
+8 dB Twist, high Mark, low
frequencies and high baud
+8 dB Twist, high Mark, high
frequencies and high baud
+10 dB Twist, low Mark, low
frequencies and low baud
+10 dB Twist, low Mark, high
frequencies and low baud
+10 dB Twist, high Mark, low
frequencies and low baud
+10 dB Twist, high Mark, high
frequencies and low baud
+10 dB Twist, low Mark, low
frequencies and high baud
+10 dB Twist, low Mark, high
frequencies and high baud
+10 dB Twist, high Mark, low
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
56
1212
-26
2222
-36
1212
57
1188
-22
2178
-19
1188
58
1188
-22
2222
-19
1188
59
1212
-22
2178
-19
1188
60
1212
-22
2222
-19
1188
61
1188
-22
2178
-19
1212
62
1188
-22
2222
-19
1212
63
1212
-22
2178
-19
1212
64
1212
-22
2222
-19
1212
65
1188
-32
2178
-26
1188
66
1188
-32
2222
-26
1188
67
1212
-32
2178
-26
1188
68
1212
-32
2222
-26
1188
69
1188
-32
2178
-26
1212
70
1188
-32
2222
-26
1212
71
1212
-32
2178
-26
1212
72
1212
-32
2222
-26
1212
frequencies and high baud
+10 dB Twist, high Mark, high
frequencies and high baud
-3 dB Twist, low Mark, low
frequencies and low baud
-3 dB Twist, low Mark, high
frequencies and low baud
-3 dB Twist, high Mark, low
frequencies and low baud
-3 dB Twist, high Mark, high
frequencies and low baud
-3 dB Twist, low Mark, low
frequencies and high baud
-3 dB Twist, low Mark, high
frequencies and high baud
-3 dB Twist, high Mark, low
frequencies and high baud
-3 dB Twist, high Mark, high
frequencies and high baud
-6 dB Twist, low Mark, low
frequencies and low baud
-6 dB Twist, low Mark, high
frequencies and low baud
-6 dB Twist, high Mark, low
frequencies and low baud
-6 dB Twist, high Mark, high
frequencies and low baud
-6 dB Twist, low Mark, low
frequencies and high baud
-6 dB Twist, low Mark, high
frequencies and high baud
-6 dB Twist, high Mark, low
frequencies and high baud
-6 dB Twist, high Mark, high
frequencies and high baud
(Noise applied from end of ACK to 200 ms after end of FSK)
Test
#
73
Mark &
Space
Freq.
& Baud
Rate
Mark &
Space
Ampl.
NOM
-30.2
Noise
Freq.
Hz
Noise
Ampl.
dBm600
20
-6.2
Comments
dBm600
52
-24 dB SNR
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
Space
74
NOM
-30.2
40
-6.2
-24 dB SNR
75
NOM
-30.2
60
-17.2
-13 dB SNR
76
NOM
-30.2
80
-17.2
-13 dB SNR
77
NOM
-30.2
120
-21.2
-9 dB SNR
78
NOM
-30.2
180
-21.2
-9 dB SNR
79
NOM
-30.2
200
-24.2
-6 dB SNR
80
81
NOM
NOM
-12.2
-12.2
300
700
-37.2
-37.2
+25dB SNR
+25dB SNR
82
NOM
-12.2
1200
-37.2
+25dB SNR
83
NOM
-12.2
1700
-37.2
+25dB SNR
84
NOM
-12.2
2200
-37.2
+25dB SNR
85
NOM
-12.2
2700
-37.2
+25dB SNR
86
NOM
-12.2
3100
-37.2
+25dB SNR
87
NOM
-12.2
3.2K
-18.2
+6 dB SNR
88
NOM
-12.2
4K
-18.2
+6 dB SNR
89
NOM
-12.2
5K
-18.2
+6 dB SNR
90
NOM
-12.2
8K
-18.2
+6 dB SNR
91
NOM
-12.2
10K
-18.2
+6 dB SNR
Table 25 - Group E, Noise Tests – Type 2 (Noise on during FSK only)
Test
#
Mark &
Space
Freq.
& Baud
Rate
Mark &
Space
Ampl.
Noise
Freq.
Hz
dBm600
93
NOM
NOM
-30.2
-30.2
20
40
-6.2
-6.2
-24 dB SNR
-24 dB SNR
94
NOM
-30.2
60
-17.2
-13 dB SNR
95
NOM
-30.2
80
-17.2
-13 dB SNR
96
NOM
-30.2
120
-21.2
-9 dB SNR
97
NOM
-30.2
180
-21.2
-9 dB SNR
98
NOM
-30.2
200
-24.2
-6 dB SNR
99
100
NOM
NOM
-12.2
-12.2
300
700
-37.2
-37.2
+25dB SNR
+25dB SNR
101
NOM
-12.2
1200
-37.2
+25dB SNR
92
Noise
Ampl.
Comments
dBm600
53
102
NOM
-12.2
1700
-37.2
+25dB SNR
103
NOM
-12.2
2200
-37.2
+25dB SNR
104
NOM
-12.2
2700
-37.2
+25dB SNR
105
NOM
-12.2
3100
-37.2
+25dB SNR
106
NOM
-12.2
3.2K
-18.2
+6 dB SNR
107
NOM
-12.2
4K
-18.2
+6 dB SNR
108
NOM
-12.2
5K
-18.2
+6 dB SNR
109
NOM
-12.2
8K
-18.2
+6 dB SNR
110
NOM
-12.2
10K
-18.2
+6 dB SNR
Table 26 - Group F, Noise Tests – Type 2 with +10 dB FSK Twist
(Noise applied from end of ACK to 200 ms after end of FSK)
Test
#
Mark &
Space
Freq.
& Baud
Rate
Mark
Ampl.
Space
Ampl.
dBm600
Noise
Freq.
Hz
dBm600
dBm600
112
NOM
NOM
-20.2
-20.2
-30.2
-30.2
20
40
-6
-6
-24 dB SNR
-24 dB SNR
113
NOM
-20.2
-30.2
60
-17
-13 dB SNR
114
NOM
-20.2
-30.2
80
-17
-13 dB SNR
115
NOM
-20.2
-30.2
120
-21
-9 dB SNR
116
NOM
-20.2
-30.2
180
-21
-9 dB SNR
117
NOM
-20.2
-30.2
200
-24
-6 dB SNR
118
119
NOM
NOM
-12.2
-12.2
-22.2
-22.2
300
700
-47.2
-47.2
+25dB SNR
+25dB SNR
120
NOM
-12.2
-22.2
1200
-47.2
+25dB SNR
121
NOM
-12.2
-22.2
1700
-47.2
+25dB SNR
122
NOM
-12.2
-22.2
2200
-47.2
+25dB SNR
123
NOM
-12.2
-22.2
2700
-47.2
+25dB SNR
124
NOM
-12.2
-22.2
3100
-47.2
+25dB SNR
125
NOM
-12.2
-18.2
3.2K
-24.2
+6 dB SNR
126
NOM
-12.2
-18.2
4K
-24.2
+6 dB SNR
127
NOM
-12.2
-18.2
5K
-24.2
+6 dB SNR
128
NOM
-12.2
-18.2
8K
-24.2
+6 dB SNR
111
54
Noise
Ampl.
Comments
129
NOM
-12.2
-18.2
10K
-24.2
+6 dB SNR
Table 27 - Group G, Noise Tests – Type 2 with –6 dB FSK Twist
(Noise applied from end of ACK to 200 ms after end of FSK)
Test
#
Mark &
Space
Freq.
& Baud
Rate
Mark &
Space
Ampl.
dBm600
Noise
Freq.
Hz
dBm600
131
NOM
NOM
-30.2
-30.2
-24.2
-24.2
20
40
-6.2
-6.2
-24 dB SNR
-24 dB SNR
132
NOM
-30.2
-24.2
60
-17.2
-13 dB SNR
133
NOM
-30.2
-24.2
80
-17.2
-13 dB SNR
134
NOM
-30.2
-24.2
120
-21.2
-9 dB SNR
135
NOM
-30.2
-24.2
180
-21.2
-9 dB SNR
136
NOM
-30.2
-24.2
200
-24.2
-6 dB SNR
137
138
NOM
NOM
-18.2
-18.2
-12.2
-12.2
300
700
-43.2
-43.2
+25dB SNR
+25dB SNR
139
NOM
-18.2
-12.2
1200
-43.2
+25dB SNR
140
NOM
-18.2
-12.2
1700
-43.2
+25dB SNR
141
NOM
-18.2
-12.2
2200
-43.2
+25dB SNR
142
NOM
-18.2
-12.2
2700
-43.2
+25dB SNR
143
NOM
-18.2
-12.2
3100
-43.2
+25dB SNR
144
NOM
-18.2
-12.2
3.2K
-24.2
+6 dB SNR
145
NOM
-18.2
-12.2
4K
-24.2
+6 dB SNR
146
NOM
-18.2
-12.2
5K
-24.2
+6 dB SNR
147
NOM
-18.2
-12.2
8K
-24.2
+6 dB SNR
148
NOM
-18.2
-12.2
10K
-24.2
+6 dB SNR
130
Space
Ampl.
Noise
Ampl.
Comments
dBm600
7 TYPE 2.5 PROTOCOL
CWD provides for a choice of treatment options in response to a CIDCW signal. A CPE may select
a CWD option by generating the appropriate Flash or Flash + DTMF signal within a programmed
period of time (typically 15 seconds) after the end of the CIDCW FSK signal.
NOTE – If the switch does not receive the CWD option signal within the required time
limits, a time out occurs, the DTMF receiver is disconnected, and default treatment of the
waiting call is implemented.
55
7.1
General
7.1.1
Type 2.5 CPE
Type 2.5 Customer Premises Equipment (CPE) shall include all the functionality of Type 2, with the
addition of supporting signaling associated with Call Waiting Deluxe (CWD). CWD is a feature that
allows a customer to control the treatment of incoming calls while the customer is Off-Hook on an
existing stable call.
7.2
Functionality
7.2.1
Type 2.5 Call Waiting Caller ID with Disposition
Type 2.5 CPE are required to perform all the Type 2 functions, plus the following function:
1) The CPE shall be able to mute the Voicepath and generate a Flash followed by a DTMF signal to
request a Call Waiting Deluxe (CWD) option.
7.3
Type 2.5 Mark Signal
Type 2 and 2.5 CPE shall accept CIDCW messages that are preceded by a Mark Signal (normally a
block of 80 bits of Mark) whose contiguous length is between:

7.3.1
50 and 110 bits.
CWD Options
The following CWD Options have been defined.
(Note: Not all options may be supported by the local telephone service provider.)
7.3.1.1
Answer
The Far-End Party is put on hold and the CPE is connected to the Waiting Party.
The CPE may select this option by signaling a Flash after receiving a CIDCW signal.
7.3.1.2
Hold
The Waiting Party is put on hold and is connected to a special Hold Announcement. The CPE
remains connected to the Far-End Party. The CPE may select this option by signaling a Flash +
DTMF 6 after receiving a CIDCW signal.
While in the Hold Call state, the CPE may select from the following CWD options.
7.3.1.2.1
Hold Return
The CPE is connected to the Held Party and the Far-End Party is put on hold. The CPE may select
this option by signaling a Flash while in the Hold Call state.
7.3.1.2.2
Hold Drop
The Far-End Party is disconnected and the CPE is connected to the Held Party.
The CPE may select this option by signaling a Flash + DTMF 7 while in the Hold Call state.
7.3.1.2.3
Conference
The Held Party and the Far-End Party are connected to the CPE forming a three party call. The CPE
may select this option by signaling a Flash + DTMF 3 while in the Hold Call state.
7.3.1.3
Forward
The Waiting Party is forwarded to the CPE’s Call Forward Don’t Answer destination (typically
voicemail). The CPE remains connected to the Far-End Party. The CPE may select this option by
signaling a Flash + DTMF 9 after receiving a CIDCW signal.
56
7.3.1.4
Announcement
The Waiting Party is connected to a special announcement chosen by the local telephone company
and then disconnected. The CPE remains connected to the Far-End Party. The CPE may select this
option by signaling a Flash + DTMF 8 after receiving a CIDCW signal.
7.3.1.5
Drop
The Far-End Party is disconnected and the CPE is connected to the Waiting Party.
The CPE may select this option by signaling a Flash + DTMF 7 after receiving a CIDCW signal.
7.3.1.6
Conference
The CPE, the Far-End Party, and the Waiting Party are connected in a three-way conversation.
The CPE may select this option by signaling a Flash + DTMF 3.
While in the Conference Call state, the CPE may select from the following CWD options.
7.3.1.6.1
Drop First
The first (original) Far-End Party is disconnected. The CPE remains connected to the second FarEnd Party (former Waiting Party). The CPE may select this option by signaling a Flash + DTMF 5
while in the Conference Call state.
7.3.1.6.2
Drop Last
The second Far-End Party (former Waiting Party) is disconnected. The CPE remains connected to
the first (original) Far-End Party. The CPE may select this option by signaling a Flash while in the
Conference Call state.
7.3.2
CWD Option Signals
The CPE CWD Option signals shall meet the following requirements.
7.3.2.1
CWD Flash Signal
The CWD Flash signal shall meet the requirements of ANSI/TIA/EIA-470-B-1997. In addition, it is
desirable that the CPE support a synchronized flash as described in ANNEX B Informative Method
for RTF inter-CPE Signaling.
7.3.2.2
CWD DTMF Signal
All DTMF transmission characteristics (other than duration) shall meet the requirements of
ANSI/TIA/EIA-470-B-1997.
7.3.2.3
CWD Option Signal Timing
The DTMF signal shall begin no sooner than 400 ms and end no later than 600 ms after the end of
the Flash signal.
The DTMF signal duration shall be 60 ms  5 ms.
57
Announcement
Flash + DTMF 8
Drop
Flash + DTMF 7
Forward
Flash + DTMF 9
CIDCW Alerting
Answer
Flash
Drop
Flash + DTMF 7
Hold
Flash + DTMF 6
Conference
Flash + DTMF 3
Return
Flash
Conference
Flash + DTMF 3
Drop First
Flash + DTMF 5
Drop Last
Flash
Figure 14 - CWD State Diagram
7.3.3
Voicepath Mute Control During CWD Option Signaling
CPE shall mute the customer’s Listening and Talking-Paths and disable the DTMF keypad no later
than the end of the Flash signal. CPE shall provide at least 50 dB of attenuation between the line and
both the customer’s Talking and Listening-Paths across the frequency band of 200 to 3200 Hz.
CPE shall restore the Voicepath and enable the DTMF keypad within 50 ms after the end of the
DTMF signal.
58
It is desired that the mute duration following the DTMF be as short as possible for systems unable to
meet the 50 ms un-mute time requirement due to the use of a secondary transmission system from the
FSK demodulator to a remote device (e.g. a cordless phone).
All CPE return to their previous
state and re-establish the
talking and listening paths
Flash per 7.3.2.1
T  600 mS
CAS
ACK
FSK Data
FLASH
T  400 mS
T  50mS
DTMF
60ms +/- 5 mS
Figure 15 - CWD Signaling Timing Diagram
8 ADJUNCT SERIES IMPEDANCE REQUIREMENTS
8.1
AC Impedance
An adjunct device shall not contribute more than 1 dB of AC loss between the frequency range of
200 to 4000 Hz, with a simulated telephone resistive AC load of 600 ohms. These conditions shall
hold when the Tip & Ring DC current is between 5 and 100 mA.
NOTE - The AC loss caused by the insertion of an adjunct should be as low as possible to
minimize the operational impact to the connected telephone.
8.2
DC Resistance
The voltage drop across an adjunct device shall not exceed 1 volt when the Tip & Ring DC current is
between 5 and 50 mA. The voltage drop shall not exceed 2 volts when the Tip & Ring DC current is
between 50 and 100 mA.
NOTE - The DC voltage drop caused by the insertion of an adjunct should be as low as
possible to minimize the operational impact to the connected telephone.
59
ANNEX A INFORMATIVE REFERENCES
[This Annex is informative only, and is not part of this Standard]
The following documents contain useful information for understanding the basis for the requirements
contained in this Standard.
1) Telcordia Technologies FR-64, LATA Switching Systems Generic Requirements (LSSGR).
2) Telcordia Technologies FR-12, Analog Display Services Interface (ADSI).
60
ANNEX B INFORMATIVE METHOD FOR RTF INTER-CPE SIGNALING
[This Annex is informative only, and is not part of this Standard]
The following diagrams and discussion contains useful information for understanding the basis for
the requirements of a synchronized flash signal. If this feature is supported, this annex provides a
guideline to its implementation. This section will be removed from future revisions of this
document, as it is intended to be included in the upcoming TIA 470.250C document for Network
Interface requirements.
1.1 Inter-CPE Signaling
The ability to request a synchronized Flash is provided by an inter-CPE signaling method that
modulates the DC line voltage with a pulse signature pattern. The benefit of the synchronized flash
is when multiple CPE are off-hook the flash is coordinated and as such can still be recognized by the
switching systems
1.1.1
Request-to-Flash Signaling
A synchronized flash provides the capability for multiple Off-Hook CPE to synchronize line Flash
signaling for the purposes of feature activation and control. In order to accomplish a synchronized
Flash, all Off-Hook CPE need to simultaneously proceed to a Momentary On-Hook state for a
specified period of time. An RTF signal has been defined to initiate a synchronized Flash for all OffHook CPE.
Type 2 CPE should be able to generate an RTF signal whenever Flash signal generation is required.
Type 2 CPE should be able to detect and respond to an RTF signal generated by another Off-Hook
CPE.
1.1.1.1
Request-to-Flash Signal Generation
Type 2 CPE should be able to generate an RTF signal with the timing pattern of T1 = 140  10 ms
On-Hook, T2 = 440  10 ms Off-Hook, and T3 = 600  10 ms On-Hook, then return to Off-Hook.
The synchronized Flash signal will be generated during the T3 interval.
T1
T2
T3
On-Hook
Off-Hook
Figure 16 - CPE State Generating RTF, Multiple CPE Off-Hook, Successful Synchronized
Flash
61
T1
T2
T3
Line High
DC level shift with
Line In Use
Figure 17 - Line State During RTF, Multiple CPE Off-Hook, Successful Synchronized Flash
If a Line High state occurs during T1 of the RTF signal, the CPE generating the RTF shall extend the
pulse width to that of a Flash signal.
NOTE - This capability allows a CPE to generate a Flash without the RTF signal if that CPE
is the only CPE Off-Hook.
T1 = Flash
Line High
Line In Use
Figure 18 - Line State During RTF, Single CPE Off-Hook
If a Line High state does not occur within 140 ms after the start of T3, all previously Off-Hook CPE
should abandon the synchronized Flash attempt and return to the Off-Hook state within 175 ms after
the start of T3.
T1
T2
T3
On-Hook
Off-Hook
Figure 19 - CPE State Generating RTF, Multiple CPE Off-Hook, And Unsuccessful RTF
62
T1
T2
T3
DC level shift with
Line In Use
Figure 20 - Line State During RTF, Multiple CPE Off-Hook, And Unsuccessful RTF
1.1.1.2
Request-to-Flash Signal Detection and Response
The CPE should be able to detect the RTF signal generated by another CPE if the DC voltage change
is  500 mV, or 5% of the Line In-Use voltage prior to the RTF, whichever is greater.
The CPE should go to a Momentary On-Hook state within 100 ms of the start of T3 to produce a
synchronized Flash, then return Off-Hook 1250  50 ms after the start of T3.
NOTE – CPE responding to an RTF remain in a Momentary On-Hook state after the start of
T3 longer than the CPE initiating the synchronized Flash so as to allow CPE supporting
CWD to signal their DTMF option without interference.
T1
T2
T3
On-Hook
Off-Hook
Figure 21 - CPE State Detecting & Responding to an RTF, Successful Synchronized Flash
T1
T2
T3
Line High
Line In Use
Figure 22 - Line State During RTF, Multiple CPE Off-Hook, Successful Synchronized Flash
If a Line High state does not exist within 140 ms after the start of T3 the CPE responding to the RTF
should abandon the synchronized Flash attempt and return to the Off-Hook state within 175 ms after
the start of T3.
63
T1
T2
T3
DC level shift with Line In Use
Figure 23 - CPE State Detecting & Responding to an RTF, Unsuccessful RTF
T1
T2
T3
DC level shift with
Line In Use
Figure 24 - Line State During RTF, Multiple CPE Off-Hook, Unsuccessful RTF
64
ANNEX C INFORMATIVE CALCULATIONS
[This Annex is informative only, and is not part of this Standard]
The following calculations contain useful information for understanding the basis for the
requirements contained in this Standard.
The signal levels in this Standard are in dBm600,or mVrms. For the purpose of this standard dBm600
refers to the level in dBm when measured across a 600 ohm load. Type 1 Level measurements
In the case when the CPE is tested in the on hook state, the CPE represents a high impedance load
The generator levels are set with an open circuit. While it is conventional for dBm to represent a
power developed in a load relative to 1mW, in the on hook example, no power is dissipated and so
dBm represents only a calculated power. The end result is that the signal will be 7.96 dB greater
than an actual 600 ohm terminated load.
Type 2 Level Measurments
In the case that the CPE is tested in the off hook state the CPE terminates the line and the voltage
generated at the load terminals will be similar to the 600 ohm load used to set the generator’s level.

Rs
900
RL
VS
600
VS source signal (open circuit)
R S = 900 ohm source resistance
R L = 600 ohm load.
V600 = signal level across 600 ohm.
We can see that:
V600 = VS 600/(900+600) = 0.4 VS
So, dBV600 = dBVS - 7.96 dB
Now, dBm600 = 10 log ([V600 2/R600]/ 1mW)
= dBV600 - 10 log(R600 x 0.001)
= dBV600 + 2.22 dB
65
V600
So, dBm600
= dBVS - 7.96 + 2.22
= dBVS - 5.74 dB
Or dBVS
= (dBm600 + 5.74) dBV
Table C1 – dBm600 Level Values
dBm600
dBV600
dBVS
V600 (mV)
VS (mV)
-49
-51.2
-43.3
2.8
6.8
-36
-38.2
-30.3
12.3
30.5
-32
-34.2
-26.3
19.5
48.4
-12
-14.2
-6.3
195
484
-4.2
-6.4
1.5
479
1189
66
ANNEX D EXAMPLES OF STEP-LIKE VOLTAGE CHANGES
[This Annex is informative only, and is not part of this Standard]
1. EXAMPLE OF STEP-LIKE VOLTAGE CHANGES ASSOCIATED WITH FSK
SIGNALS NOT PRECEDED BY POWER RINGING.
V1
V7
V2
V6
V3
V5
V4
V1
V2
T2
+50.0
+16.0
28
V3
T3
V4
T4
V5
T5
-16.0 32 -40.0 970 -16.0 30
Voltages are in VDC, time is in msec.
(FSK is sent during T4.)
67
V6
T6
V7
+16.0
72
+50.0
2. EXAMPLES OF STEP-LIKE VOLTAGE CHANGES FOR FSK PRECEDED BY
POWER RINGING
Example 1
V1
V3
V4
V2
V1
T1
+56.0
720
V2
T2
V3
T3
V4
+33.6 3360 +56.0 440 +52.0
Voltages are in VDC, time is in msec.
(FSK is sent during T2.)
68
T4
160
Example 2
V3
V7
V1
V4
V2
V6
V5
V1
V2
T2
V3
+50.0
+22.0
80
+78.0
T3
V4
T4
V5
T5
1280
+4.0 80 -76.0 480
Voltages are in VDC, time is in msec.
(FSK is sent during T6.)
69
V6
T6
V7
-36.0
1080
+78.0