TR30.3/98-09-095
Draft 1 PN 4256
TIA/EIA-496-B
INTERFACE BETWEEN
DATA CIRCUIT-TERMINATING EQUIPMENT (DCE)
AND THE
PUBLIC SWITCHED TELEPHONE NETWORK (PSTN)
PN 4256 Draft 1
September 1998
Copyright 1998 TIA - All Rights ReservedWorking Draft
Draft 1 PN 4256 September 9, 1998
Table of Contents
1.0
INTRODUCTION ...........................................................................................................................................1
2.0
SCOPE ..............................................................................................................................................................1
3.0
DEFINITIONS .................................................................................................................................................2
3.1
BREAK INTERVAL ...........................................................................................................................................2
3.2
CONFORMING TELEPHONE NETWORK INTERFACE ..........................................................................................2
3.3
DIAL TONE .....................................................................................................................................................2
3.4
DATA ARRANGEMENT ....................................................................................................................................3
3.5
DATA CIRCUIT TERMINATING EQUIPMENT (DCE) ..........................................................................................3
3.6
DATA MODE ...................................................................................................................................................3
3.7
INTERDIGITAL INTERVAL ................................................................................................................................3
3.8
LONGITUDINAL BALANCE COEFFICIENTS ........................................................................................................3
3.9
LONGITUDINAL VOLTAGE ...............................................................................................................................3
3.10 MAKE INTERVAL ............................................................................................................................................3
3.11 METALLIC VOLTAGE.......................................................................................................................................3
3.12 MODE INDICATOR LEADS ...............................................................................................................................3
3.13 NETWORK INTERFACE ....................................................................................................................................3
3.14 OFF-HOOK ......................................................................................................................................................3
3.15 ON-HOOK .......................................................................................................................................................3
3.16 PART 68 JACK CONFIGURATION ......................................................................................................................4
3.16.1 Fixed Loss Loop Configuration .............................................................................................................4
3.16.2 Permissive Configuration .......................................................................................................................4
3.16.3 Programmable Configuration .................................................................................................................4
3.17 PERCENT BREAK.................................................................................................................................................4
3.18 PORT...................................................................................................................................................................4
3.19 PUBLIC SWITCHED TELEPHONE NETWORK (PSTN) ............................................................................................4
3.20 REGISTERED EQUIPMENT ....................................................................................................................................4
3.21 RINGER EQUIVALENCE NUMBER (REN) .............................................................................................................4
3.22 TIP AND RING .....................................................................................................................................................4
3.23 VOICE MODE ......................................................................................................................................................4
4.0
TECHNICAL REQUIREMENTS ..................................................................................................................5
4.1
ON-HOOK STATE ............................................................................................................................................5
4.1.1
DC Resistance, Tip to Ring, Tip and Ring to Ground (REN) ................................................................5
4.1.2
AC Impedance, Tip to Ring ...................................................................................................................5
4.1.3
AC Impedance, Tip and Ring to Ground .............................................................................................10
4.2
OFF-HOOK STATE .........................................................................................................................................10
4.2.1
Off-Hook DC Resistance .....................................................................................................................10
4.2.2
Off-Hook AC Impedance not in Part 68 ..............................................................................................10
4.2.3
Maximum On-Hook Duration without Disconnect not in Part 68 .......................................................11
4.3
CALL ORIGINATION.......................................................................................................................................12
4.3.1
Dial Pulses Address Signaling not in Part 68 ......................................................................................12
4.3.2
Dual Tone Multifrequency (DTMF) Address Signaling Not in Part 68 except limitations on max
signal power on DTMF ........................................................................................................................................16
4.3.3
Automatic Calling Criteria not in Part 68 ...........................................................................................19
4.4
CALL ANSWER NOT IN PART 68 ....................................................................................................................20
4.4.1
Ring Detector Sensitivity .....................................................................................................................20
4.4.2
Automatic Answer Delay Requirements ..............................................................................................21
4.5
DISCONNECT NEVER IN PART 68 ...................................................................................................................23
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4.5.1
Disconnect Coordination .....................................................................................................................23
4.5.2
Minimum On-Hook Duration - Automatic Calling ..............................................................................23
4.6
TRANSMISSION .............................................................................................................................................23
4.6.1
Maximum Power, On-Hook 68.314(a)(1)(i)&(ii) ................................................................................23
4.6.2
Signal Power, Off-Hook ......................................................................................................................23
4.6.3
Maximum Metallic Voltages, 4 kHz to 6 MHz 68.308(e)(1)(i)&(ii)....................................................26
4.6.4
Maximum Longitudinal Voltages ........................................................................................................27
4.6.5
Longitudinal Balance 68.310 ...............................................................................................................30
4.6.6
Echo and Echo Control Device Compatibility Never in part 68 ..........................................................33
4.7
ELECTRICAL ENVIRONMENTAL CONDITIONS (NORMAL) NOT SPECIFIED EXCEPT LOOP VOLTAGE & RESISTANCE
SPECIFIED IN FIG 68.3(A)........................................................................................................................................... 36
4.7.1
Telephone Loop Potentials and Currents .............................................................................................36
4.7.2
Telephone Loop Battery Reversals ......................................................................................................38
4.7.3
Induction from Power Lines on Telephone Loops ...............................................................................38
ANNEX A
DATA ARRANGEMENTS AND ASSOCIATED JACKS .............................................................39
A.1
DATA ARRANGEMENTS ................................................................................................................................ 39
A.l.1
Ports .....................................................................................................................................................39
A.2
REGISTERED JACKS.......................................................................................................................................44
A.2.1
RJ11C (Common Reference – Voice Jack)..........................................................................................44
A.2.2
RJ16X (Common Reference – Voice Jack) .........................................................................................45
A.2.4
RJ36X (Common Reference – Voice Jack) .........................................................................................47
A.2.5
Data Jacks ............................................................................................................................................47
A.2.6
Programming Resistor Calculation ......................................................................................................48
A.2.7
RJ41S (Common Reference – Universal Data Jack) ............................................................................48
A.2.8
RJ45S (Common Reference – Programming Data Jack) .....................................................................49
ANNEX B
RINGER EQUIVALENCE NUMBER (REN) ................................................................................49
ANNEX C
PHYSICAL AND ENVIRONMENTAL STRESSES......................................................................51
C.1
DROP STRESSES (NORMAL) ..........................................................................................................................51
C.1.1
Drop Stresses - Equipment Unpackaged ..............................................................................................52
C.1.2
Equipment Not Normally Customer Carried ........................................................................................52
C.2
VIBRATION - TRANSPORTATION ENVIRONMENT (NORMAL)..........................................................................53
C.3
TEMPERATURE AND HUMIDITY CYCLE .........................................................................................................53
ANNEX D
ABBREVIATED TESTING PROCEDURES .................................................................................53
D.1
GENERAL ......................................................................................................................................................53
D.2
GROUNDING METAL CHASSIS .......................................................................................................................53
D.3
OVERLOAD PROTECTION ..............................................................................................................................53
D.4
CONNECTION AND WIRING ...........................................................................................................................54
D.4.1
Physical Separation ..............................................................................................................................54
D.4.2
Power Cords.........................................................................................................................................54
D.4.3
Bushings...............................................................................................................................................54
D.5
DIELECTRICS ................................................................................................................................................55
D.6
FAULT ISOLATION CIRCUITRY .......................................................................................................................56
ANNEX E
E.1
NETWORK SIGNALING WEIGHTING FUNCTIONS ............................................................... 56
PROTECTION AGAINST TRANSMISSION INTERRUPTIONS ................................................................................56
ANNEX F
ELECTRICAL ENVIRONMENTAL STRESSES..........................................................................63
F.1
NORMAL TELEPHONE LINE POTENTIALS AND CURRENTS .............................................................................63
F.l.1 Permanent Signal Release Test (Normal) ................................................................................................ 63
F.1.2
Switchboard Operation (Normal) .........................................................................................................64
F.2
GROUND PATH CURRENT SURGES (ABNORMAL) ..........................................................................................64
Copyright 1998 TIA - All Rights ReservedWorking Draft
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F.3
TRANSIENTS .................................................................................................................................................64
F.3.1
Surges Associated with Protectors .......................................................................................................64
F.3.2
Transient Voltages during Call Setup (Normal) ...................................................................................66
F.4
POWER LINE FAULTS AND LINE CROSSES (ABNORMAL) ...............................................................................66
ANNEX G
G.1
MAXIMUM VOLTAGES AND CURRENTS - FAULT CONDITIONS .......................................................................67
ANNEX H
iv
ELECTRICAL HAZARD PREVENTION ......................................................................................67
RELATED DOCUMENTS ...............................................................................................................68
Copyright 1998 TIA - All Rights ReservedWorking Draft
TR30.3/98-09-095
Draft 1 PN 4256
TIA/EIA-496-B
This standard is being reissued to reflect the changes in the network specifications that have occurred in the
harmonization of the FCC CFR Part 68 and the Canadian CS-03.
1.0
INTRODUCTION
This standard is one of a series of technical standards on Data Circuit-Terminating Equipment (DCE) prepared by
EIA Technical Committee TR-30. With the advent of the Federal Communication Commission's (FCC) Registration
Program, there has developed a need for standards for the interface between DCE and the Analog Public Switched
Telephone Network (PSTN). This document is intended to fill that need. In this standard, the term "Data
Arrangement" is used to include the DCE and other equipment that may be associated with it (See Appendix A). In
addition, the term "Network Interface" is used when referring to the interface between a Data Arrangement and the
PSTN. This standard is intended to be useful to manufacturers of Data Arrangements, suppliers of communications
services, and to the users of such equipment and services for data transmission.
This standard establishes technical requirements for interfacing and connecting a Data Arrangement to the PSTN for
purposes of data transmission. Compliance with these requirements is intended to assure minimum acceptable
compatibility with the PSTN.
In accordance with EIA Engineering Publication EP-7B, two categories of performance standards are specified;
mandatory and advisory. Mandatory performance criteria are designated by the word "shall" and advisory
performance criteria are designated by the word "desirable".
Mandatory performance levels delineated in this standard represent the minimum acceptable levels for Data
Arrangement operation at the interface to the PSTN. Advisory or desirable criteria represent operational goals for
the Data Arrangement at the Network Interface. These criteria are included in an effort to assure product
compatibility in as many applications as possible. Advisory criteria are also included when their attainment will
enhance the overall performance level of the Data Arrangement at the Network Interface.
Where both a mandatory and an advisory level are specified for the same criterion, the advisory level represents a
goal currently identifiable as having distinct compatibility advantages, performance advantages or both, toward
which future product designs should strive.
In some cases, implementation within the Data Arrangement of equipment options may be required to meet certain
location oriented operating requirements. This flexibility is needed to accommodate differences between
applications and in a few cases significant differences between network switching systems. Therefore, in order to
assure satisfactory performance, two items are needed: equipment design compliance to this interface standard and a
process for configuring the Data Arrangement to the requirements of its telephone network application.
2.0
SCOPE
This standard specifies the interface between a Data Arrangement and the PSTN. A Data Arrangement includes the
Data Circuit-terminating Equipment and any associated equipment used in conjunction with it. The standard
includes functional, mechanical, electrical and operational specifications of this Network Interface. This equipment
may be subject to the applicable environmental and safety rules specified in other standards.
This standard is based upon telecommunication plant characteristics at the Network Interface. However, this
standard may be used as a basis for interfacing Data Arrangements to other facilities and equipment, such as a
Private Branch Exchange (PBX) as defined in Standard TIA/EIA-464B or a private switched network.
Conformance to this standard is intended to assure satisfactory user service under almost all conditions when
connected to a Conforming Telephone Network Interface (see Section 3). However, conformance will not assure
compatibility under abnormal conditions (e.g. prolonged loss of commercial electric power at network equipment
locations or periods of abnormally high traffic loads). Also, conformance cannot assure interface compatibility in all
possible installations because of the wide variety of transmission facilities (e.g. subscriber carrier systems) and
switching equipment in the United States.
Copyright 1998 TIA - All Rights ReservedWorking Draft
Draft 1 PN 4256 September 9, 1998
The requirements in this standard are intended to cover technical requirements of Part 68 of the FCC Rules that
apply to this interface. However, as Part 68 is subject to change, some differences gm and is not to be may exist and
readers are cautioned that this Standard is intended to augment and is not to be considered a substitute for Part 68.
This Standard includes a subset of the requirements from Part 68 to promote a uniform interpretation by designers of
Data Arrangements of the rules as they apply to such equipment.
With respect to some interface parameters, the limitations necessary to assure satisfactory operation with the PSTN
are more restrictive than the limitations necessary only to preclude harm. For completeness, physical and
environmental conditioning stresses (specified in Part 68) are included in Appendix C.
The requirements of this standard cover those interface characteristics that are either essential, or optional but
beneficial, to successful call origination, answer and disconnection, and transmission of data between Data
Arrangements interfacing with the PSTN. The interface, as specified in Part 68, is at the connection point of a
standard plug and jack. Standard plugs and jacks are described in Subpart F of Part 68 or in nationwide tariffs in
accordance with 68.104. Representative jacks are described in Appendix A.
The requirements reflect the relevant characteristics of the PSTN including the voltages, both transient and steady
state under normal and abnormal conditions, which may appear on the interface leads from sources on the network
side of the interface.
As does Part 68, this standard covers requirements for Data Arrangements to operate on "loop start" access lines to
the PSTN. It does not cover operation on "ground start" lines.
This standard does not cover operation with "custom calling" features, such as call forwarding, provided by some
telephone central offices. It is intended to include requirements necessary to preclude interference with the use of
such features where the Data Arrangement is bridged on a line where such features are provided. Note, however,
signals used to provide these features may cause errors or interruptions in the transmission of data.
The techniques used for the transmission of data over this interface are beyond the scope of this standard.
3.0
DEFINITIONS
Where applicable, the use in this standard of technical terms found in IEEE Standard 100- 1977 is in accordance
with the definitions in that standard. The following definitions are for terms either not found in or where the usage
differs from the IEEE Standard.
3.1
Break Interval
See Section 4.3. 1. 1
3.2
Conforming Telephone Network Interface
One which:
1.
Complies with the network requirements specifically stated in this standard. (E.g. Section 4.6.6.1.)
2.
Complies with the network requirements implied in this standard. For example, when a stated requirement is
that a Data Arrangement must present a certain impedance to the network and respond to certain voltages and
frequencies (e.g., ring detector) it is implied that a conforming network will provide voltages and frequencies
that fall within the limits described when presented with the impedance required of the Data Arrangement.
Note: The impairment parameters of the network are specified in a separate standard developed by ANSI
Technical Subcommittee TlQl.
3.3
Dial Tone
A network generated signal of 350 Hz and 440 Hz (± 0.7%) that indicates that the network equipment is ready to
receive either DTMF signals or dial pulses. This is sometimes referred to as "precise dial tone".
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Draft 1 PN 4256 September 9, 1998
3.4
Data Arrangement
A single item or group of items presented at the customer side of the Network Interface for data transmission
purposes and includes all equipment that may affect the characteristics at the interface. For further definition see
Appendix A.
3.5
Data Circuit Terminating Equipment (DCE)
In this document, the term Data Circuit Terminating Equipment is to be considered synonymous with the term
modem.
3.6
Data Mode
An operating state of a Data Arrangement in which it is configured for data communication. See Voice
3.7
Interdigital Interval
See Section 4.3. 1. 1.
3.8
Longitudinal Balance Coefficients
The metallic-to-longitudinal balance coefficient is an FCC requirement to prevent harm to the network. The
longitudinal-to-metallic balance coefficient relates to the data performance. The coefficients are normally expressed
in decibels. In real systems, these coefficients are normally not equal in magnitude. See Section 4.6.5.
3.9
Longitudinal Voltage
One-half of the vector sum of the potential difference between the tip connection and earth ground, and the ring
connection and earth ground for the tip, ring pair. See Section 4.6.4.
3.10
Make Interval
See Section 4.3-1.1
3.11
Metallic Voltage
The potential difference between the tip and ring connections. See Section 4.6-3.
3.12
Mode Indicator Leads
These leads, designated Mode Indicator (MI) and Mode Indicator Common (MIC) are one means used to indicate to
the DCE whether the arrangement is in Voice Mode or Data Mode. (Also see Voice Mode and Data Mode.)
3.13
Network Interface
For the purposes of this standard, the Network Interface is the point of interconnection between the data arrangement
and the PSTN. See Appendix A.
3.14
Off-Hook
Operating state of a Data Arrangement in which the communication link is enabled for voice, data communication or
network signaling.
3.15
On-Hook
Operating state of a Data Arrangement in which the communication link is disabled. During this state, the Data
Arrangement presents a defined high impedance to the network.
Comment: The terms "Off-Hook" and "On-Hook" derive from the original telephone usage in which they refer to
the position of the hand set with respect to the cradle of the telephone.
Copyright 1998 TIA - All Rights ReservedWorking Draft
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Draft 1 PN 4256 September 9, 1998
3.16
Part 68 Jack Configuration
3.16.1
Fixed Loss Loop Configuration
A Part 68 data jack configuration in which the transmission path loss is adjusted by the Local Exchange Carrier
(LEC) to a fixed value by means of an attenuator to assure optimum power into the network when used with a Data
Arrangement having a fixed output power of -4 dBm.
3.16.2
Permissive Configuration
A Part 68 jack configuration in which no special provision is made to optimize signal power into the network. The
output power of Data Arrangements using this configuration is limited to a maximum of -9 dBm independent of loop
loss.
3.16.3
Programmable Configuration
A Part 68 data jack configuration in which signal power transmitted from Data Arrangements is controlled by means
of a resistor (located in the jack), the value of which is chosen by the LEC on the basis of the particular loop loss to
assure optimum power to the network.
Comment: Best Data Arrangement performance is usually obtainable with programmable or fixed loss loop data
jacks.
3.17 Percent Break
See Section 4.3. 1. 1
3.18 Port
See Appendix A
3.19 Public Switched Telephone Network (PSTN)
The telephone networks in the United States commonly accessed by ordinary telephones, key telephone systems,
private branch exchange trunks, and Data Arrangements. Completion of the circuit between the calling and called
party in this network requires network signaling in the form of dial pulses or dual tone multi-frequency (DTMF)
signals.
3.20 Registered Equipment
Equipment that has been registered in accordance with Part 68
3.21 Ringer Equivalence Number (REN)
A number that denotes that fraction of the permissible on hook load that any given unit of the customer premises
equipment is putting on the public network. See Section 4.0 and Appendix B.
3.22 Tip and Ring
The pair of conductors in the network interface used for transmission.
Comment: Tip and Ring are common usage terms for the two conductors of the local telephone loop. The terms
originated in reference to the phone plug used to make connections in manual switchboards where one side of the
line makes contact with the tip of the plug, and the other to the ring contact immediately behind the tip of the plug.
Note: The color of the tip and ring conductors, and their relative position to each other in a standard jack at the
Network Interface is not guaranteed. Wiring in one and two pair cable for the tip connection is commonly colorcoded green while that for the ring connection is commonly color-coded red.
3.23 Voice Mode
An operating state of a Data Arrangement in which it is configured for voice communication. See Data Mode.
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Copyright 1998 TIA - All Rights ReservedWorking Draft
Draft 1 PN 4256 September 9, 1998
4.0
TECHNICAL REQUIREMENTS
The Technical Requirements for Data Arrangements in this standard are specified at the Network Interface.
Requirements in several subsections of Sections 4.1 are a function of the REN of the Data Arrangement and are
indicated by the designation "REN" in parentheses at the end of the associated heading. The requirements stated are
that for an REN of 1.0 where the REN can range in value from 0.0 to 5.0 in increments of 0.1. For Data
Arrangements having an REN different than 1.0, the applicable requirement is obtained by scaling the specified limit
as indicated in Appendix B.
4.1
On-Hook State
4.1.1
DC Resistance, Tip to Ring, Tip and Ring to Ground (REN)
See Figure B.1
The dc resistance tip to ring, tip to ground, and ring to ground shall be greater than 25 megohms for values of
applied dc voltage (of either polarity) to 100volts, and greater than 150 kilohms in the range 100 to 200 volts.
4.1.2
AC Impedance, Tip to Ring
4.1.2.1 Minimum Impedance at Ringing Frequencies (REN) 68.312(b)(iii) Criteria 3 ma
See Figure B.1
During the application of ringing signals (ac plus dc) defined in Figure 4.1.2- 1, the impedance (defined as the
quotient of the applied ac voltage divided by the resulting rms current) shall be greater than the values specified in
the figure. The total dc current which flows as a result of ringing voltages defined in Figure 4.1.2-1, shall not exceed
0.6mA. It is desirable that the current not exceed 0.2 ma.
In addition, to assure the proper performance in response to ringing (assure a voltage consistent with the requirement
in Figure 4.4.1-1), the following requirement must also be met:
For ringing types A through Q, the design (average of all units) impedance shall meet or exceed the limit specified in
Figure 4.1.2-1. The design impedance at 17 Hz shall exceed 10 kilohms with an applied voltage of 55 Vrms
superimposed on up to + 105 Vdc.
4.1.2.2 Maximum Impedance at Ringing Frequencies
not found eliminated the min 40K ohms Z
During the application of simulated ringing signals defined in Figure 4.1.2-1, the magnitude of the impedance shall
be less than 40 kilohms. Data Arrangements intended for use on loops, which will have additional ringing detection
circuitry in use at the same time, need not comply with this 40-kilohm requirement.
4.1.2.3 Minimum Impedance - 5 Hz to 200 Hz (REN)
Never in Part 68
See Figure B.1
The impedance, tip to ring, at frequencies from 5 Hz to 200 Hz shall meet the following requirements:
1.
For all ringing types other than C and D, the impedance shall be in the acceptable region in Figure 4.1.2-2 for
voltages of 1 to 10 Vrms.
2.
For ringing types C and D, the impedance shall be in the acceptable region in Figure 4.1.2-3 for voltages of 1 to
10 Vrms.
4.1.2.4 Minimum Impedance - 200 Hz to 3200 Hz (REN)
never in Part 68
See Figure B.1
The impedance, tip to ring, at frequencies from 200 Hz to 3200 Hz shall meet the following requirements:
1.
For all ringing types other than M and N the impedance at frequencies from 200 Hz to 1633 Hz and from 1633
Hz to 3200 Hz shall be within the acceptable regions shown in Figure 4.1.2-4a for voltages of up to 3 Vrms
applied across the tip and ring terminals.
Copyright 1998 TIA - All Rights ReservedWorking Draft
5
Draft 1 PN 4256 September 9, 1998
Ringing
Type(4)
A
B(3)
Frequency
Hz(5)
AC Signal
Vrms(5)
DC Bias
Vdc(1)(5)
Min. IMP.
Ohms(2)(5)
20  3
40 - 130
0 ± 105
7000
30  3
40 - 130
0 ± 52.5
5000
15.3 to 34
40 - 130
0 ± 105
8000
>34 to 49
62 - 130
0 ± 1055
8000
>49 to 68
62 - 150
0 ± 105
8000
(1) Most central offices supply ± 52.5 Vdc. Where range extension is used the voltage may be as high as ± 105
Vdc. Part 68 does not specifically note this higher extension voltage in its Table 1.
(2) In this table, and throughout this document, a Ringer Equivalence Number (REN), as defined in Part 68,
with a value of 1.0 is assumed.
(3) Type B is intended to encompass all ringing frequencies.
(4) Designation required by Part 68 to be on a label as part of the REN.
(5) The values listed may differ from those found in Part 68. If so, those listed in Part 68 shall be used.
AC Impedance Pre-Trip Requirements (REN = l)
Figure 4.1.2-1
6
Redo table – 68.312 (a)
Copyright 1998 TIA - All Rights ReservedWorking Draft
Draft 1 PN 4256 September 9, 1998
Minimum On-Hook Impedance (REN =5)
5 to 200 Hz
FIGURE 4.1.2-2
Copyright 1998 TIA - All Rights ReservedWorking Draft
7
Draft 1 PN 4256 September 9, 1998
Maximum On-Hook Impedance (REN)
200 to 3200 Hz
FIGURE 4.1.2-3a
8
Copyright 1998 TIA - All Rights ReservedWorking Draft
Draft 1 PN 4256 September 9, 1998
Maximum On-Hook Admittance (REN)
200 to 3200 Hz
FIGURE 4.1.2-3b
Copyright 1998 TIA - All Rights ReservedWorking Draft
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Draft 1 PN 4256 September 9, 1998
2.
Figure 4.1.2-4a (impedance) is equivalent to Figure 4.1.2-4b (admittance). Both figures have been provided as
an aid to understanding this requirement.
4.1.3
AC Impedance, Tip and Ring to Ground
4.1.3.1 Minimum Impedance at Ringing Frequencies (REN) 68.312(b)(v) - OK
The tip-to-ground and ring-to-ground impedance in the presence of the simulated ringing signals (ac plus dc)
presented in Figure 4.1.2-1 shall be greater than 100 kilohms.
4.1.3.2 Minimum Impedance - 60 Hz to 660 Hz
never in Part 68
The tip-to-ground and ring-to-ground impedance, over the frequency range of 60 to 660 Hz, shall exceed 20 kilohms.
These impedance requirements apply for voltages up to 50 Vrms at 60 Hz, up to 15 Vrms at 180 Hz and up to 1
Vrms at higher frequencies.
4.2
Off-Hook State
4.2.1
Off-Hook DC Resistance
4.2.1.1 Maximum DC Resistance, Tip to Ring
68.314(c)(1)&(2)
The off-hook tip to ring dc voltage versus current characteristic shall conform to the limitations given in Figure
4.2.1-1 for all off-hook functions. However, it is desirable that the minimum impedance be no less than 90 ohms.
4.2.1.2 Minimum DC Resistance, Tip and Ring to ground
not in Part 68
The off-hook dc resistance from tip to ground and ring to ground shall be greater than 250 kilohms, in both the Voice
and Data Modes, over the range of loop current indicated in Figure 4.7. 1-1.
4.2.2
Off-Hook AC Impedance not in Part 68
The following criteria apply over the range indicated in Figure 4.7. 1-1.
4.2.2.1 Minimum Return Loss
It is desirable that the return loss conforms to the values of the table below:
Frequency
Minimum Return Loss (RL)
260 - 500 Hz
7.0 dB (SRL Low)
560 - 1960 Hz
11.0 dB (ERL)
2200 - 3400 Hz
14.0 dB (SRL Hi)
RL (dB) = 20 Log10
Z+ Z(r)
Z - Z(r)
Where Z is the impedance of the Data Arrangement and Z(r) is the reference impedance (600 ohms in series with a
2.16 F capacitor). For definitions see IEEE Standard 743.
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Copyright 1998 TIA - All Rights ReservedWorking Draft
Draft 1 PN 4256 September 9, 1998
Note: Some network equipment automatically adjusts transmission parameters based on the sum of cable pair
resistance. The use of such equipment is increasing. The proper operation of these devices is predicated upon the
assumption that loop is directly proportional to observed resistance. The accommodation of such devices and of
customer equipment that limit loop current may impact this voltage-versus-current curve where the acceptable region
above 26 ma is under study.
Customer Installation Off-Hook Tip to Ring
DC Voltage versus Current Characteristics
Figure 4.2.1-1
4.2.2.2 Minimum Impedance, Tip and Ring to Ground - 60 Hz to 660 Hz
The tip-to-ground and ring-to-ground impedance, over the frequency range of 60 to 660 Hz, shall exceed 10 kilohms.
These requirements apply for voltages up to 50 Vrms at 60 Hz, up to 15 Vrms at 180 Hz and up to 1 Vrms at higher
frequencies.
4.2.3
Maximum On-Hook Duration without Disconnect
4.2.3.1 Calling Station
not in Part 68
When in the off-hook state, a Data Arrangement shall not generate an on-hook indication (as may, for example,
occur in transferring between Voice and Data Modes) greater than 100 milliseconds in duration, except to signal
disconnect or for flash signaling.
4.2.3.2 Called Station
When in the Off-hook State, it is desirable that a Data Arrangement should not generate an on-hook indication
greater than 2 seconds in duration except to signal disconnect.
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Draft 1 PN 4256 September 9, 1998
4.3
Call Origination
4.3.1
Dial Pulses Address Signaling
not in Part 68
The criteria in this Section ensure that dial pulses are compatible with dial pulse receivers. The criteria apply to both
mechanical and semiconductor devices. Failure to meet the following criteria can cause improper registration of
digits, missed digits or pulse splitting. This can result in misdirected calls, time-outs, or other undesirable effects.
The following requirements apply when dial pulses are generated by Data Arrangements that use a dial pulsing
contact bridged by a passive RC contact protection network (resistor in series with a capacitor). In addition, an
optional suppression device (e.g. zener diode) may be placed across the contact. The dial pulse contacts of
mechanical devices are assumed to be ideal. That is, upon opening, the device contact impedance is essentially
infinite; and upon closing, there is no voltage drop across the contact. While only mechanical devices approximate
this ideal switch, the assumption is that the switching times of either mechanical or semiconductor devices are very
short relative to the magnitude of the pulsing intervals.
4.3.1.1 Definitions
1.
Break Interval
The dial pulse break interval begins at the instant the pulsing switch stops conducting and ends at the instant the
switch starts conducting.
2.
Make Interval
The dial pulse make interval begins at the instant the pulsing switch starts conducting and ends at the instant the
pulsing switch stops conducting.
3.
Percent Break
The percent break is the percentage ratio of the dial pulse break interval to the sum of the break plus make
intervals.
4.
Interdigital Interval
The Interdigital interval is the interval between the end of the last break interval of a digit and the beginning of
the first break interval of the succeeding digit.
4.3.1.2 Dial Requirements
1.
Dial pulse address signaling shall consist of a sequence of momentary openings (breaks) of the closed loop in
response to pulsing contact operation. (When tip is bridged to ring through the circuit off-hook dc resistance, the
loop is closed.) The numerical value of each dialed digit shall be identical to the number of break intervals in
each dialed pulse train, except for the digit "O" which shall be represented by 10 break intervals.
2.
The pulsing contact shall operate at repetition rates between 8 and 11 pulses per second.
3.
The percent break of dial pulses shall be between 58 and 64 percent. (The break interval of a single pulse shall
be between 53 and 80 milliseconds.)
4.
The duration of pulsing contact arcing, if any, at the initiation of a break interval, shall not exceed 0.2
millisecond with its protective network in a resistive circuit and with a potential of 50 volts across the open
contact.
5.
The requirements of dial repetition rate (pulses per second) and minimum 58 percent break are satisfactory if the
pulsing contact is shunted by a capacitive-resistance network of 0.1 microfarad, the smallest permissible value,
in series with a resistance of 100 to 600 ohms. The contact may also be shunted with a suppression device (e.g.
zener diode) having a breakdown voltage of at least 300 volts.
6.
If bridging RC network capacitance exceeds 0.1 microfarad, the speed and percent break requirements for the
dial pulses shall be modified as shown in Figure 4.3.1-1. If the suppression device break down voltage is
decreased below 300 volts, the speed and percent break requirements for the dial pulses shall be modified as
shown in Figure 4.3.1-2. If the network capacitance is increased above 0.1 microfarad and the suppression
device voltage is decreased below 300 volts, Figure 4.3.1-3 shows which compensation curve to use.
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This diagram is used t determine the allowed area of operation of a dial for a given capacitor in its protective
network. Thus for the capacitance of 1 F, the parameters of the dial pulses must lie in the hexagon bounded by the
sloping lines marked 1 F, the 58 percent break line, the 8 PPS line, the 11 PPS line and the 64 percent break line.
Percent Break and PPS Limits
As a Function of Network Capacitance
For Devices which Generate Pulses
Figure 4.3.1-1
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This diagram is used to determine the allowed area of operation of a dial for a given suppression device in the
protective network. Thus for the voltage of 225 volts, the parameters of the dial pulses must lie in the hexagon
bounded by the sloping lines marked 225 volts, the 58 percent break line, the 8 PPS line, the 11 PPS line and the 64
percent break line.
Percent Break and PPS Limits
As a Function of Suppression Device Voltages
For Devices which Generate Dial Pulses
Figure 4.3.1-2
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Required Compensation for Combination Suppression
Devices and RC Network Protection
Figure 4.3.1-3
7.
Where the pulsing contact shunts the transmission network during dial pulsing, the path through the transmission
network shall be opened during pulsing and the operation of the contact used to open/close the path shall be
coordinated (make before break) with the pulsing contact to preclude spurious break intervals.
8.
Each break interval plus the succeeding make interval (if any) and each break interval plus the proceeding make
interval (if any) shall fall within the area of speed and percent break specified above.
9.
The minimum ac impedance across the tip and ring terminals for voltages from 1 to 10 Vrms and across the
device during break intervals shall conform to the requirements of Figures 4.1.2-2 or 4.1.2-3, as appropriate.
10. During the break intervals of the dial pulse train, the steady state resistance from tip to ring with tip grounded
and tip to ring with ring grounded shall be at least 50 kilohms. This resistance is to be measured with a voltage
applied across tip and ring of:
a)
Up to 300 volts when the RC contact protection network shunts the pulsing contact.
b) Up to the maximum voltage that will not cause the suppression device to break down when a suppression
device shunts the pulsing contact.
11. During make intervals the steady state resistance from tip and ring shorted together relative to ground shall be at
least 150 kilohms. This resistance is measured with voltages up to 300 volts.
12. During make intervals, the equipment shall have a steady state voltage versus current characteristic that satisfies
the conditions given in Figure 4.2.1-1.
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13. If both numeric and alphabetical dial designations are provided, they shall be in accordance with the Figure
4.3.1-4.
14. At the initiation of a make interval, the total duration of transients as evidenced by a series of short makes and
breaks shall not exceed 3 milliseconds in duration.
15. Spurious breaks other than those of the above paragraph 14 during any off-hook interval while in the address
signaling state (after dial tone but prior to dial pulsing, during an Interdigital interval, during a make interval,
and after dial pulsing through a period of time equivalent to an Interdigital interval) shall not exceed 1
millisecond in duration.
16. Spurious make intervals shall not occur during a break interval.
17. If a voice transmission path (to an electro/acoustical transducer used to make call progress signals audible or for
other purposes) is removed during dialing of each digit, it is desirable that it be reestablished as soon as possible
after dialing is completed, and in no case shall it be removed for longer than 2 seconds after a single digit is
dialed.
18. Whenever a special pulsing termination is bridged across tip and ring during dialing (to overcome the
detrimental effects which a lumped inductance, e.g., a repeat coil, can have on dial pulses) the following
standards apply:
a)
The termination shall be inserted prior to or during the first break of each dialed digit and shall remain until
the last break of the digit has occurred.
b) The termination shall be removed when the transmission path is restored.
c)
Removal of the termination shall not cause a spurious break (inductive open) that causes the loop current to
fall below 17 milliamperes for longer than 1.0 millisecond.
19. If dialing is initiated automatically, the first digit shall be sent between 70 milliseconds and 10 seconds after
reception of dial tone. The interdigital time shall be between 600 milliseconds and 3 seconds. Desirable
minimum and maximum interdigital times are 700 milliseconds and 1 second, respectively.
SYMBOL
LETTERS
NUMBER OF PULSES
1
1
2
ABC
2
3
DEF
3
4
GFH
4
5
JKL
5
6
MNO
6
7
PQRS
7
8
TUV
8
9
WXYZ
9
0
OPERATOR OR OPER
10
DIAL PULSE ASSIGNMENTS
FIGURE 4.3.1-4
4.3.2
Dual Tone Multifrequency (DTMF) Address Signaling
signal power on DTMF
Not in Part 68 except limitations on max
The following criteria are intended to ensure proper DTMF address signaling through the voice transmission path
for:
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1.
DTMF address signaling from station equipment on users’ premises to DTMF receivers in PBX equipment on
users’ premises.
2.
DTMF address signaling from station equipment on users' premises transmitted either directly or through PBX
equipment to DTMF receivers in central offices. (This relies upon the characteristics of DTMF receivers in
central offices and the transmission characteristics of PBX are specified in TIA/EIA-464B, as well as acceptable
transmission characteristics of PBX central office trunk facilities.)
3.
DTMF address signaling from station equipment on user premises transmitted through PBX equipment to
DTMF receivers in other PBX's which comply with TIA/EIA-464B. (This relies upon the transmission
characteristics of PBX's specified in TIA/EIA-464B, as well as acceptable transmission characteristics of interPBX tie line facilities.)
4.3.2.1 Definitions
1.
Pulse duration is the time interval in which the instantaneous DTMF signal amplitude is at 90 percent, or
greater, of its steady state amplitude.
2.
Rise time of a DTMF pulse is the time for the instantaneous DTMF signal amplitude to reach 90 percent of
steady state amplitude from the time at which both of the component frequencies (taken separately) first exceed 55 dBm.
3.
Fall Time of a DTMF pulse is the time for the DTMF signal to fall to a point where at least one of the
component frequencies is -55 dBm or less from the time at which the instantaneous DTMF signal amplitude is
90 percent of its steady state value.
4.
Interdigital interval is the time when either or both of the component frequencies are at a level less than -55
dBm.
5.
Cycle time equals the sum of the four intervals defined above (rise time, pulse duration, fall time and interdigital
interval).
6.
Signal-ON time is composed of rise time, pulse duration, and fall time.
7. Signal-OFF time is any time that is not "signal-on" time.
4.3.2.2 Signaling Frequencies
DTMF signals consist of two tones, one from a high group of four frequencies and one from a low group of four
frequencies, which represent each of the characters shown below.
Nominal High Group Frequencies (Hz)
1209
1336
1477
1633
Nominal
679
1
2
3
A
Low Group
770
4
5
6
B
Frequencies
852
7
8
9
C
(Hz)
941
*
0
#
D
The * and # characters are required to ensure compatibility with the custom call features of some switching systems.
Note: The designation A, B, C, and D used here are for reference purposes only. The actual button designations of
the 1633 Hz series are specified in other documents applicable to systems that use those frequency combinations.
4.3.2.3 DTMF Transmission Characteristics
DTMF signals shall have the following characteristics when measured into a 600-ohm load connected across the tip
and ring. The requirements apply, except as noted, over the range of loop current indicated in Figure 4.7. 1-1.
4.3.2.3.1 Inband DTMF Signal Power
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For a transmitter powered by loop current, the full amplitude of the DTMF signal levels shall fall within the
minimum and maximum level of figure 4.3.2-1
DTMF signal levels generated by a transmitter not powered by loop current shall meet the following:
Minimum level per frequency:
Maximum power per frequency pair:
Low Group
-10.5 dBm
High Group
-8.5 dBm
0 dBm
The maximum difference in levels between two frequencies in a frequency pair shall not exceed 4 dB, and the level
of the high-frequency component shall equal or exceed the level of the low-frequency component.
Nominal level per frequency:
Low Group
-6.0 dBm
High Group
-4.0 dBm
4.3.2.3.2 Frequency Deviation
The frequencies shall be within ± 1.5 percent of their nominal values.
4.3.2.3.3 Rise Time
Each of the two tones of a DTMF signal shall attain at least 90% of fun amplitude of the two-tone signal within 5
milliseconds from the time the signal exceeds -55 dBm.
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DTMF Signal Levels for Transmitters
Powered by Loop Current
FIGURE 4.3.2-1
4.3.2.3.4 Extraneous Frequency Components
The total power of all extraneous signals in the voiceband above 500 Hz during a DTMF pulse shall be at least 16
dB below the power of each of the two fundamental components of the DTMF pulse.
4.3.2.3.5 Tone Leak
During Signal-OFF periods of the automatic calling process, before and after DTMF pulsing and during interdigital
intervals, no DTMF component shall leak into the transmission path at a level higher than -55 dBm.
4.3.2.3.6 Transient Voltage
Peak transient voltages generated by the DTMF transmitter shall be constrained to occur within the first 5
milliseconds of ON time of the DTMF signal and shall have a peak level no higher than 12 dB above the zero-topeak voltage of the full amplitude of the two-tone signal.
4.3.3
Automatic Calling Criteria
4.3.3.1 Dial Tone Detection
not in Part 68
It is desirable that initiation of network addressing be in response to the detection of dial tone.
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4.3.3.1.1. Dial Tone Levels
Dial tone levels can be expected to range from -29 to -10 dB m per frequency (no more than 6-dB difference
between component signals).
4.3.3.1.2 Start Dial Delay
Some central office equipment may not accept network-signaling information earlier than 70 milliseconds or later
than 5 seconds from the time dial tone is applied.
4.3.3.2 Minimum Wait for Called Station Answer
It is desirable that a minimum of 40 seconds be allowed after completion of dialing, before a call is abandoned and
retried.
4.3.3.3 DTMF Pulsing Rate for Automatic Dialers
Minimum duration of a two-frequency signal:
50 milliseconds
Minimum interdigital interval:
45 milliseconds
Maximum interdigital interval:
3 seconds
Minimum cycle time:
100 milliseconds
4.4
Call Answer
4.4.1
Ring Detector Sensitivity
not in Part 68
Ring detectors indicate the presence of ring voltage on the line.
Note: Most Data Arrangement manufacturers design to ringer type B.
4.4.1.1 Ringing Signals
Ring Detectors shall respond to the appropriate voltages between the tip and ring terminal as given in Figure 4.4.1-1.
4.4.1.2 Non-Ringing Signals
It is desirable that ring detectors do not respond to the following signals described in (a) through (f). These signals
may be applied during automatic LEC maintenance procedures. Such tests are applied sequentially; the series of
tests may last as long as 12 seconds if all tests are applied.
a)
a longitudinal voltage applied to both the tip and ring terminals with respect to ground as follows:
(1) up to 50 Vrms at 60 Hz,
(2) up to 15 Vrms at 180 Hz, or
(3) any combination of 60 Hz and 180 Hz of up to 50 Vrms with the 180 Hz voltage restricted to the range of 0
to 15 Vrms;
b) signals of 10 Vrms or less at 24 Hz superimposed on -70 to +70 Vdc on the tip terminal with the ring terminal
grounded, on the ring terminal with the tip terminal grounded, or on both tip and ring terminals with respect to
ground;
c)
ac signals of 10 V = or less at any frequency from 5 to 1000 Hz, tip to ring or on both the tip and ring terminal
with respect to ground;
d) ground on the tip terminal or the ring terminal;
e)
dc voltages (steady state conditions) from 0 to + 202 volts, tip to ring with neither the tip nor the ring terminal
grounded or with either grounded or on both the tip and the ring with respect to ground;
f)
signals of 3 Vrms or less from 1000 Hz to 2000 Hz between tip and ring;
It is also desirable that:
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a)
Data Arrangements not go off-hook in response to signals of 5 Vrms or less from I kHz to 5 kHz, between
tip and ring;
b) If a Data Arrangement does not comply with the impedance requirements described in Section 4.1.4 and the
real part of the admittance at 24 Hz from tip to ring, tip to ground and ring to ground are all more than 40
microsiemens (micromhos), ring detectors should not respond to the application of 33 Vrms or less at 24 Hz
for 2 seconds or less, tiptoeing or tip and ring with respect to ground.
c)
4.4.2
Dialing (at 8 to 11 pulses per second) or switchhook transients generated as a result of such operations by
the Data Arrangement or by the associated telephone set or a bridged telephone set when connected on a
zero length loop to any of the simulated central office terminations shown in Figure 4.4.1-2 or when
connected to the simulated long loop circuit shown in Figure 4.4.1-3.
Automatic Answer Delay Requirements
It is desirable that automatic answering equipment responds to detection of a ringing signal by going off hook within
7 seconds. Following the off hook a minimum of 2 seconds shall be allowed to elapse before data transmission is
allowed.
RINGING
FREQUENCY
AC SIGNAL
DC BIAS
TYPE
Hz
Vrms
Vdc
A
17 - 23
40 - 130
0 ±105
A
27 - 33
95 - 130
0 ±52.5
B
15.3 - 68
40 - 150
0 ±105
This requirement applies for all ringing types when the signals are applied in repetitive bursts of 2 seconds out of
every 6 seconds, where an individual burst may be as short as 0.8 second.
The requirement also applies for ringing types A and B, when the signals are applied in the following manner:
1.
Repetitive bursts of 1 second out of every 4 seconds when an individual burst may be as short as 0.6
seconds
2.
At least one ringing burst of minimum 0.5 second duration in any 4 second period at voltages = 40 Vrms.
NETWORK RINGING SIGNALS
FIGURE 4.4.1-1
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Short Loop False Ringing Detection Circuit
FIGURE 4.4.1-2
Ringer or ring detector of data arrangement under test shall not respond when dial of switch hook of telephone set is
operated.
Long Loop False Ringing Detection Circuit
FIGURE 4.4.1-3
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4.5
Disconnect
never in Part 68
To disconnect, a Data Arrangement must establish the On-hook State defined in Section 4.1.
4.5.1
Disconnect Coordination
It is desirable that disconnect be coordinated at the calling and called stations so that neither remains off-hook
unnecessarily tying up parts of the network. If a Data Arrangement remains off-hook after the far end station
disconnects, it may receive signals from the network that could appear as spurious data signals.
4.5.2
Minimum On-Hook Duration - Automatic Calling
It is desirable for a Data Arrangement which has disconnected a call that it has originated to maintain the on-hook
state for at least 1.5 seconds in order to provide adequate time for recognition of a new request for dial tone.
4.6
Transmission
4.6.1
Maximum Power, On-Hook
68.314(a)(1)(i)&(ii)
In the On-hook State, the power within the frequency band of 200 to 4000 Hz delivered into a 600-ohm resistive
termination at the tip and ring terminals shall not exceed -55 dBm.
This requirement applies with the Data Arrangement connected to the loop simulator shown in Figure 4.7.1-1.
4.6.2
Signal Power, Off-Hook
The following limitations apply to the signal power delivered into a 600 ohm resistive termination at the tip and ring
of the Network Interface, and in all off-hook operating states of the Data Arrangement and apply over the range of
loop current indicated in Figure 4.7. 1-1.
4.6.2.1 Maximum Power - Network Control Signaling
68.308(b)(2)(ii)
The maximum 3 second average power of signals transmitted for network control signaling shall not exceed 0 dBm.
4.6.2.2 Maximum Data Signal Power
4.6.2.2.1 Data Arrangement Sources
The following limitations apply to the total power for all transmitted data sequences.
a) The maximum signal power for Data Arrangements, which connect to the network via a Voice Jack, shall not
exceed -9 dBm when averaged over any 3-second interval. No manufacturing tolerance is allowed which would
permit this power to be exceeded by any unit of equipment.
68308(b)(4)(iii)
b) The maximum signal power for Data Arrangements which connect to the network via a Universal Data Jack 1
used in a Fixed-Loss Loop configuration shall not exceed -4 dBm when averaged over any 3 second interval.
c)
68.308(b)(4)(ii)
The maximum signal power, averaged over any 3 second period, for Data Arrangements which connect to the
network via a Universal Data Jack or a Programmed Data Jack1 for use in the "programmed" configurations
shall be programmed to not exceed the power specified in Figure 4.6.2-2 for each step, when averaged over any
3 second interval (resistance connected in the Jack between the programming leads PR and PC).
68.308(b)(4)(i)
For alternatives (b) and (c) the maximum signal power may exceed (for a particular Data Arrangement) the specified
maximum level by as much as 1.0 dB, provided that the power averaged over all Data Arrangements having the same
registration number complies with the specified maximum.
Note: The values specified in this section and in Figure 4.6.2-2 may differ from those specified in Part 68. If so, the
values specified in Part 68 shall be used.
4.6.2.2.2 Requirements at Equipment-to-Equipment (E-E) Ports
gain in 68.30895)
not in Part 68 except through transmission
Level Protected Ports
See Appendix A.
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In operating states of concern, equipment providing a Level Protected port must meet, at any Network Interface to
which a through transmission path can exist in any operating state, the requirements of Section 4.6.2.2.1 with a tone
applied to the Level Protected port as follows:
The tone sources shall have an impedance either consistent with the intended application or that which reflects a 600
ohm load across tip and ring of the Network Interface. The tone shall be applied at frequencies from 200 Hz to 4000
Hz over a range of input power from power A (see below) to power B (see below).
Programming Resistor (Rp)(1)(2)(3)(4)
Ohms
Signal Power(3)
dBm
150
-1
336
-2
569
-3
866
-4
1,240
-5
1,780
-6
2,520
-7
3,610
-8
5,490
-9
9,200
-10
19,800
-11
open
-12
Notes:
1) Tolerance of Rp is ±1%
2) The voltage impressed on resistor Rp by the data equipment shall be such as not to cause power dissipation in
Rp in excess of 50 milliwatt.
3) Tolerance of Signal Power is ± 1.0 dB
4) See Appendix A-6 for a recommended circuit using the programming resistor.
Signal Power
Programmed-Configuration Resistor Steps
FIGURE 4.6.2-2
Power A is the available power that results in a power of 6 dB below the highest permitted power when averaged
over a 3 second interval. The highest permitted power will either be that which is limited by equipment capabilities
or that specified in Section 4.6.2.2. 1, whichever is lower.
Power B is an available power at least 16 dB higher than power A.
Available power is the power into the load when load and source impedance is matched.
Unprotected or Fully Protected Ports See Appendix A.
In any operating state of concern, equipment providing an Unprotected or Fully Protected port shall meet, at any
Network Interface to which a through transmission path exists in any operating state, the following requirements:
1.
24
The gain (the ratio of the power into the load to the available power with 600 ohm source and load impedance)
at all frequencies in the range of 200 Hz to 4000 Hz shall, when averaged over all those equipment entities
having the same registration number, shall not be greater than 0 dB. However, the gain for an individual unit
Copyright 1998 TIA - All Rights ReservedWorking Draft
Draft 1 PN 4256 September 9, 1998
(installation) of the equipment may be as large as 1.5 dB. These values may differ from the corresponding
values specified in Part 68. If so, the values specified in Part 68 shall be used.
2.
Where the equipment provides a dc voltage or a current to the connected registered equipment (e.g., for
powering of Electro/acoustic transducers), the dc conditions provided shall be within those provided by the loop
simulator circuit specified in Figure 4.7. 1-1.
3.
The connector provided at the Unprotected or Fully Protected port may be a jack physically identical to the FCC
Standard Voice or Data jacks, as appropriate (See Appendix A). However, if the Equipment is designed to
accommodate the connection of either Programmed or Fixed Loss Loop registered data equipment at the
Equipment-to-Equipment interface, whether by means of a jack physically identical to a Universal or
Programmed Data Jack or by other connecting means, the following limitations and/or requirements apply:
a)
If the equipment is configured for connection at the Network Interface by means of a Standard Voice Jack (i.e.
the equipment is registered for Permissive connection) and,
(i)
If the Unprotected or Fully Protected port is configured for connection to Programmed registered
equipment, provision for terminating the PR and PC leads from the programmed registered
equipment shall be included at the port. This termination shall include a resistance between the PR
and PC terminals of at least 9200 ohms, or
(ii)
If the Unprotected or Fully Protected port is configured for connection to Fixed Loss Loop
registered equipment, the transmission path between the Network port and the Unprotected port
shall include a loss (600 ohm source and load) of at least 6 dB at all frequencies from 200 Hz to
4000 Hz.
b) If the equipment is configured for connection at the Network Interface by means of an eight pin, keyed plug for
connection to an FCC Standard Data Jack (or by means of a 50 pin connector configured to mate with a 50 pin
Data Jack of the type described in Appendix A):
(i)
Pins for PR and PC lead shall be terminated in the equipment with a resistance of at least 9200ohm between these two leads or the leads shall be carried through the equipment to the appropriate
pins of the Network Interface connector.
(ii)
The electrical length of the leads between the Unprotected port and the Network Interface,
including any and all wiring, within the equipment and external cables, shall not exceed 25 feet
unless the tip and ring leads are physically separated from (not in the same cable as) the other
leads.
(iii)
There is no restriction on the length of the leads between the protective circuits of a Fully
Protected port and the port itself. However, the wiring from the protective circuits to the Network
Interface must comply with the requirement of (ii) above.
4.6.2.3 Maximum Power, 3995 Hz to 4005 Hz
1.
The maximum transmitted power of data signals in the 3995 to 4005 Hz range shall be 18 dB below the
maximum transmitted power, permitted by Section 4.6.2.2 above, in the 200-4000 Hz band. 68.308(c)(1)
2.
If a through transmission path to the tip and ring of the Network Interface for signals from another equipment is
included, the loss at any frequency in the 600 to 3995 Hz band shall not exceed, by more than 3 dB, the loss at
any frequency in the 3995 to 4005 Hz band. This limitation applies with a signal source which has an
impedance consistent with the intended application (or, if appropriate, a source which reflects a 600 ohm load
across the tip and ring of the Network Interface) connected across the appropriate terminals of the interface for
the other equipment and with the tip and ring of the Network Interface terminated with a 600 ohm resistive load. 68.308(c )(2) exce
4.6.2.4 Minimum Data Signal Power
not specified in Part 68
For Data Arrangements intended to connect to the network via a voice jack, it is desirable that the minimum average
signal power shall not be less than -13.0 dBm.
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4.6.2.5 Billing Protection
68.314(a)(1)
During the first 2 seconds after going to an off-hook state in response to an incoming call, the data arrangement shall
not apply data signals to the line.
4.6.2.6 False Disconnect Protection
68.314(d)(1)
The Data Arrangement shall not apply signals in the band 2450 to 2750 Hz unless equal power is applied in the band
800 to 2450 Hz. It is desirable that it not be applied after the first 2 seconds.
4.6.3
Maximum Metallic Voltages, 4 kHz to 6 MHz
68.308(e)(1)(i)&(ii)
Note: The values listed in this section may differ from those found in Part 68. If so, the values in Part 68 shall be
used.
Limitations:
a) 4 kHz to 270 kHz:
The root-mean-squared voltage (1), averaged over 100 milliseconds, at the tip and ring of
the Network Interface of the Data Arrangement, in all possible 8 kHz bands within the indicated frequency
range, shall not exceed the maximum indicated in Figure 4.6.3-1.
b) 270 kHz to 6 MHz:
The root-mean-square (rms) value of the metallic voltage components in the frequency
range of 270 kHz to 6 MHz shall, averaged over 2 microseconds, not exceed -15 dBV. This limitation applies
with a metallic termination having impedance of 135 ohms.
Conditions:
not specified except par 3
The limitations apply in all operating states of Data Arrangement. In the Off-hook State, they are applicable over the
range of loop current specified in Figure 4.2.1-2. The limitations apply in the Data Mode for all possible transmitted
signals (or data sequences) and for all possible terminations, lead lengths and signal wave shapes, which may be
connected to the Equipment-to-Equipment, interface.
The limitations apply in the Data Mode, in the Voice Mode, during the DTMF signaling and with the tip and ring
connected to a resistive termination as specified for the various frequency bands. Appropriate terminations are
indicated in Figure 4.6.4-4. In the Voice Mode, the limitations apply with a 1000 Hz acoustic signal applied to any
Electro/acoustic transducer used for transmitting acoustic signals adjusted for any power of up to -13 dBm delivered
into a 600 ohm resistive termination across the tip and ring of the Network Interface.
Registered terminal equipment and registered protective circuitry with provision for through transmission from other
equipment shall comply with the limitations with a 1000 Hz tone applied during normal operation. Registered
protective circuitry for data shall also comply with the tone level 10 dB higher than expected during normal
operation.
68.308(g)(3)
The same conditions, as for Level Protected ports, apply for Fully Protected ports except that the 1000 Hz tone
power should be at the maximum that connected equipment can be expected to generate.
1
1. Average magnitudes may be used for signals, which have peak to RMS ratios of 20 dB or less. RMS limitations
must be used instead of average values if the peak to RMS ratio of the interfering signal exceeds this value.
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Center
Metallic
Frequency
Max RMS Voltage in
Terminating
of 8 kHz Band
8 kHz Band Centered at f
impedance
8 kHz to 12 kHz
-(6.4 + 12.6 log f) dBV
300 ohms
12 kHz to 90 kHz
(23 - 40 log f) dBV
135 ohms
90 kHz to 266 kHz
-55 dBV
135 ohms
Where: f = center frequency in kHz of each of the possible 8 kHz bands dBV = 20 log 10 (voltage) and
voltage is in volts.
MAXIMUM METALLIC VOLTAGES - 4 kHz to 270 kHz
Figure 4.6.3-1
4.6.4
68.308(e)(1)(i)
Maximum Longitudinal Voltages
Limitations:
a)
Voltage in the 100 Hz to 4 kHz Frequency Range
68.308(d)
The weighted root-mean-squared voltage averaged over 100 milliseconds that is the resultant of all the component
longitudinal voltages in this band after weighting according to the curve in Figure 4.6.4-1 shall not exceed the
maximum indicated in Figure 4.6.4-2. The weighting curve in Figure 4.6.4-1 has an absolute gain of unity at 4 kHz.
b)
Voltage in the 4 kHz to 6 MHz Frequency Range
68.308(e)(2)(i)&(ii)
4 kHz to 270 kHz
The root mean squared voltage (2) averaged over 100 milliseconds, at the tip and ring of the Network Interface of the
Data Arrangement in all of the possible 8 kHz bands within the indicated frequency range, shall not exceed the
maximum indicated in Figure 4.6.4-3.
270 kHz to 6 MHz
The root-mean square (rms) value of the longitudinal voltage components in the frequency range of 270 kHz to 6
MHz shall, averaged over 2 microseconds, not exceed -30 dBV. This limitation applies with a longitudinal
termination having impedance of 90 ohms.
Conditions: Applicable conditions are as specified in 4.6.3.
2
Average magnitudes may be used for signals that have peak to RMS ratios of 20 dB or less. RMS limitations
must be used instead of average values if the peak to RMS ratio of the interfering signal exceeds this value.
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Weighting Function Response
FIGURE 4.6.4-1
Frequency Range
Voltage
Longitudinal
Terminating
Impedance
100 Hz to 4 kHz
-30 dBV
500 ohms
Maximum Longitudinal Voltage – 100 kHz to 4 kHz
FIGURE 4.6.4-2
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Metallic
Terminating
Impedance
600 ohms
Draft 1 PN 4256 September 9, 1998
Center
Frequency
Of 8 kHz Band
8 kHz to 12 kHz
Max RMS
Voltage in 8 kHz
Centered at f
-(18.4 + 20 log f) dBV
Longitudinal
Terminating
Impedance
Metallic
Terminating
Impedance
500 ohms
300 ohms
12 kHz to 42 kHz
(3 – 40 log f) dBV
90 ohms
135 ohms
42 kHz to 266 kHz
-62 dBV
90 ohms
135 ohms
Where: f = center frequency in kilohertz of each of the possible 8 k Hz bands and dBV = 20log10
(voltage), where voltage is in volts.
Maximum Longitudinal Voltage – 4 kHz to 270 kHz
FIGURE 4.6.4.3
Identical but tables not labeled in Part 68
Resistive Terminations
FIGURE 4.6.4-4
fig 68.308(a)
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4.6.5
Longitudinal Balance
68.310
4.6.5.1 Minimum Metallic to Longitudinal Balance (Harm Balance)
The metallic-to-longitudinal balance coefficient, BALANCE M-L is expressed as:
Em
BALANCEM-L = 20 log10-----EL
Where EL is the longitudinal voltage produced across a 500 ohm longitudinal termination and Em is the metallic
voltage across the tip and ring of the Network Interface when a voltage (at any frequency in the specified frequency
range) is applied from a balanced 600 ohm metallic source. The source voltage is adjusted such that E m equals 0.775
Vrms (0 dBm) when a 600 ohm termination is substituted for the Data Arrangement. An illustrative test
configuration that satisfies the above conditions is shown in Figure 4.6.5-1 that other means may be used to
determine the balance coefficient specified herein, provided the FCC has approved them.
The minimum balance coefficients as specified in Figure 4.6.5-2 at frequencies up to 4 kHz shall be satisfied. The
minimum balance coefficient shall be equaled or exceeded at all the values of loop current specified in Figure 4.2.12. The minimum balance requirements specified shall be equaled or exceeded under all reasonable applications of
ground to exposed conductive surfaces of the equipment, with all possible Data Terminal Equipment (DTE) interface
lead terminations which may affect compliance, with any connections to external ground. In addition, the balance
requirement shall be equaled or exceeded with and without any optional connection, if it exists, of an interface-signal
ground reference (power supply secondary) to green wire ground.
Metallic-to-Longitudinal Balance Test Circuit
FIGURE 4.6.5-1
30
fig 68.310-1(a)
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Minimum
Balance
Frequency Range
State
(dB)
(Hz)
on-hook
60
200 to 1000
40
1001 to 4000
40
200 to 4000
off-hook
MINIMUM METALLIC TO LONGITUDINAL BALANCE
200 Hz to 4 kHz
FIGURE 4.6.5-2 table under 68.310(b)
4.6.5.2 Minimum Longitudinal-to-Metallic Balance (Performance Balance)
Never in Part 68
The longitudinal-to-metallic balance coefficient, BALANCEL-M is expressed as:
EL
BALANCEL-M = 20 log10--------Em
where EL is the applied longitudinal voltage and Em is the resultant metallic voltage. For equipment that has
longitudinal impedance which is voltage (EL) dependent, the balance requirement is applicable with applied rms
voltages for EL of 50 volts at 60 Hz, 15 volts at 180 Hz and 1 volt at higher frequencies superimposed on a 60 Hz
voltage of up to 50 volts and in the off-hook state, over the range of loop current indicated in Figure 4.7.1-1 where
appropriate.
For equipment that has longitudinal impedance, which is independent of voltage, up to 50 Vrms, the balance is not
dependent upon the presence of the 60 Hz voltage. For such equipment, the procedure for measuring the
longitudinal-to-metallic balance described in IEEE Standard 455 is satisfactory. Figure 4.6.5-3 is representative of
the test configuration used for a one port device.
4.6.5.2.1.Minimum Balance, Data Mode - Off Hook
Off-hook in the Data Mode the longitudinal-to-metallic balance shall be in the acceptable region of Figure 4.6.5-4 at
all frequencies from 600 to 4000 Hz.
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Note:
1. The capacitance of C1 is maintained within 0.2 F of C2
2. The oscillator provides 0 to 10 Vrms over the frequency range
3. Adjusts R3 to balance the test circuits to a minimum of 20-dB greater balance than the value in figure
4.6.5-2.
Longitudinal-to-Metallic Balance Test Circuit
FIGURE 4.6.5-3
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Off-Hook Data Longitudinal-to-Metallic Balance Requirement
FIGURE 4.6.5-4
4.6.6
Echo and Echo Control Device Compatibility
Never in part 68
Data Arrangements intended to operate over terrestrial circuits without active echo control devices must be able to
tolerate echoes delayed up to 100 milliseconds. Those intended to operate over satellite circuits shall be able to
tolerate echoes delayed up to 700 milliseconds.
4.6.6.1 Echo Control Device Operation
There are two types of echo control devices that may be encountered on a PSTN connection, Echo Suppressors and
Echo Cancellers.
Echo suppressors control echoes by inserting a loss of at least 30 dB in the transmission path opposite the direction
of the transmitted signal. This loss is removed after a period of approximately 100 milliseconds of quiet time. When
signals are present simultaneously in both directions for a period of 50 milliseconds the echo suppressors enter the
"double talk" state in which 6 to 15 dB of loss is added to both directions of transmission.
Echo cancellers on the other hand only add loss to the echoed signal and do not effect the transmission path. After a
training (converging) period of approximately 500 milliseconds, the echo canceller will assure an echo path loss of at
least 40 dB. During the "double talk" state the level of echo cancellation may diminish slightly, but as with normal
operation the transmission path will not be affected.
4.6.6.2 Echo Control Device Compatibility
To preclude unintentional disabling of echo suppressors during the transmission of data, the 100 milliseconds
average signal power in the 1900 Hz to 2350 Hz band shall not exceed, at any time, the 100 millisecond average
power in the rest of the voice frequency band (300 Hz to 1900 Hz and 2350 Hz to 3000 Hz), when the power is
weighted in accordance with a function which lies in the acceptable region shown in Figure 4.6.6- 1.
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To ensure that, if echo cancellers are present on a connection, they are properly converged, it is desirable that Data
Arrangements, as a part of the handshaking procedures, transmit a signal having the full frequency spectrum of the
line signals to be transmitted, for at least 500 milliseconds in each direction (one direction at a time). It is sufficient
to transmit noise having a flat spectrum over the 300 Hz to 3000 Hz band at the data signal level. However, it
should be noted that even a properly converged echo canceller would begin to diverge when a narrow band tone is
applied to the connection for a sustained period of time. Significant divergence may begin within 1 minute.
Therefore half duplex Data Arrangements which send data interspersed with single frequency idle tones may
encounter initial echoes when switching to the data mode after a period of several minutes in the idling state.
Echo Suppressor Disabling
Prevention Weighting Function
FIGURE 4.6.6-1
4.6.6.3 Echo Control Device Disabling
Echo control devices are equipped with tone operated disablers. Because of the different approaches to echo control,
used by echo cancellers and echo suppressors, it has been recognized that some Data Arrangements (e.g., frequency
division duplex), that require echo suppressors to be disabled, might benefit from an active echo canceller.
Therefore a selective disabling scheme has been specified. Data Arrangements that only require echo suppressors to
be disabled shall provide the echo suppressor disabling signal and those that require all echo control devices on a
connection be disabled shall provide the echo canceller disabling signal. These signals shall comply with the
following restrictions:
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To disable Echo Suppressors, either Data Arrangement shall transmit a signal, at data level, in the 2010 Hz to 2240
Hz band for at least 400 milliseconds. If the disabling tone is transmitted by the answering Data Arrangement the
duration shall be extended to at least 2.4 seconds to ensure that the originating Data Arrangement has received 400
milliseconds of disabling tone. During this transmission the signal power outside of this band shall be at least 15 dB
below that in the band.
If both Echo Cancellers and Echo Suppressors are to be disabled, either Data Arrangement shall transmit a signal for
a period of 3.3 ± 0.7 seconds, at data level, comprised of 2100 ± 15 Hz tone, with a reversal of 180o in its phase
every 450 ± 25 milliseconds. The reversals in phase shall be accomplished such that the phase is changed by 180' ±
10' within a 1 millisecond period and that the amplitude of the 2100 Hz tone in not more than 3 dB below its steady
state value for more than 400 microseconds. The same restrictions relative to out of band power, as stated above,
apply.
The Data Arrangement not transmitting the disabling tone shall not transmit signals above -46 dBm in the 200 Hz to
4000 Hz band.
After the echo control device has been disabled, signal power in the 300 to 3000 Hz band in either direction of
transmission will keep it disabled provided that then Data Arrangement complies with the following restrictions:
1) The power of the signal in the 300 to 3000 Hz band, when weighted in accordance with a function in the
appropriate acceptable region in Figure 4.6.6-2 and averaged over any 100 milliseconds is not lower than the
minimum acceptable disabling tone power specified above.
2) If the signal spectra from both Data Arrangements can consist of a single frequency being transmitted
simultaneously for more than 100 milliseconds, the difference between the two frequencies shall be greater than
5 Hz.
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Maintenance of Echo Suppressor Disabling
State Weighting Function
FIGURE 4.6.6-2
4.7
Electrical Environmental Conditions (Normal)
not specified except loop
voltage & resistance specified in fig 68.3(a)
4.7.1
Telephone Loop Potentials and Currents
Data Arrangements shall continue to operate upon encountering any of the following potentials and currents at its
Network Interface.
4.7.1.1 Loop Battery Voltage
Values in the following paragraph are provided for guidance only.
The dc voltage applied to conductors of individual loops is normally in the range of 19 to 78.75 Vdc and negative
with respect to ground. In addition, in certain cases where range extension is employed, the voltage applied to one
conductor may be up to +52.5 Vdc with respect to ground while the voltage applied to the other conductor may be up
to -52.5 Vdc with respect to ground. The voltage source between tip and ring provided by subscriber carrier systems
may be floating with respect to ground and may be as low as 7.5 Vdc. Some subscriber carrier systems provide even
less than 7.5 Vdc.
4.7.1.2 Loop Current
The following paragraph is provided for guidance only.
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The range of loop current is that which results when the voltages and loop resistances are varied over the ranges
specified in Figure 4.7.1-l. If the values in this figure differ from those specified in Part 68, the ones specified in
Part 68 will be used.
4.7.1.3 Ringing Signals
Ringing signals are repetitive bursts that may be as short as .8 seconds recurring at intervals of typically 5 to 6
seconds. A partial burst shorter than .8 seconds may occur on the initial ring. During the silent interval central
office battery is applied to the line. The ac and dc voltages are applied between the tip and ring conductors. Central
office ringing signal source voltages are as shown in Figure 4.4.1-1. Some subscriber carrier systems provide lower
ringing voltages.
The “loop current range” is the range of dc current which would flow in the tip and ring with the loop simulator
circuit connected across the tip and ring of the Network Interface to the equipment and with the resistance R2,
voltage V and polarity switch varied over the specified range of conditions.
Loop Simulator Circuit
FIGURE 4.7.1-1
4.7.1.4 Test Voltages
1) Voltages applied for test purposes from the Central Office to on-hook equipment, may be up to a maximum of
202 Vdc between the tip and ring conductors (either polarity) or between either conductor and ground. (Positive
with respect to ground). For voltages that are negative with respect to ground, the maximum that can be applied
to the loop with the equipment on-hook is 56.5 Vdc.
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2) AC maintenance testing signals of up to 10 Vrms also may be applied on either the tip or ring conductor with
respect to each other, from tip to ground or from ring to ground, in the frequency range 5 to 1000 Hz, except in
the frequency range 17 to 26 Hz where ringing voltages given in Figure 4.4.1-1 are applicable, when the
equipment is in the on-hook state.
3) If a Data Arrangement does not meet the impedance requirements specified in Section 4.1.4 and if the real part
of the admittance of the Data Arrangement at 24 Hz from tip to ring, tip to ground and ring to ground are all less
than 40 microsiemens (micromhos), automatic loop testing equipment may apply a signal of 33 Vrms, or less, at
24 Hz for 2 seconds or less, tip to ring or tip with respect to ground or ring with respect to ground.
4.7.1.5 DC Loop Current Continuity
1.
Call Setup
DC loop current interruptions may occur during call setup regardless of whether the Data Arrangement is at the
originating or terminating end of the call. These interruptions usually occur within 750 milliseconds (switching
interval) after the terminating end of the connection goes off-hook (answer). They are usually not longer than 350
milliseconds in duration.
2.
Network Release
When the originating end of a connection disconnects, the terminating end loop current may eventually be
interrupted, but such interruptions vary among Central Offices, among lines terminated on an individual Central
Office and among calls to a particular line. Loop current interruptions also occur in some situations at the
originating end after the terminating end disconnects. This interruption may be used to supplement other means of
disconnection. Data Arrangements that are intended to respond may provide a method of disconnect based on the
table below:
(*)
Reject
Accept
Option 1(*)
=5 milliseconds
 8 milliseconds
Option 2
= 85 milliseconds
 90 milliseconds
Note:
Option 1 is most commonly used.
Data Arrangements should not respond to interrupts that occur during call setup. That is, both the calling
and called Data Arrangement should reject interrupts for up to 750 milliseconds after the called station goes
off-hook.
4.7.2
Telephone Loop Battery Reversals
Some Central Offices provide a reverse tip and ring polarity when a toll call is being dialed.
4.7.3
Induction from Power Lines on Telephone Loops
Induction resulting from magnetic fields surrounding power distribution systems can cause the appearance of
longitudinal mode (tip and ring to ground) voltages, usually not exceeding 50 Vrms at 60 Hz and 15 Vrms at 180 Hz
or a combined voltage of 50 Vrms or less. Since the induced voltage is in series with and generally distributed along
the loop or metallic facility involved, the longitudinal mode voltage will be a function of the far end termination of
the loop as well as the loop characteristics. At the tip and ring terminals of the Network Interface, the source
impedance of induced voltages may be as low as 1 00 ohms and as high as 750 ohms. For voltages greater than 50
Vrms, the source impedance normally will be at least 400 ohms.
With connected station equipment on-hook, such longitudinal voltages may, depending on the loop impedance and
the Central Office terminating impedance, produce metallic open circuit voltages of up to approximately 5 Vrms at
the tip and ring terminals of the Network Interface, with source impedance between 400 ohms and 3000 ohms.
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ANNEX A Data Arrangements and Associated Jacks
A.1
Data Arrangements
The term Data Arrangement is used in this standard for any Data Circuit-Terminating Equipment that interfaces with
the PSTN by itself or in conjunction with associated equipment. When Data Circuit-Terminating Equipment is used
with associated equipment in a Data Arrangement, the requirements of this standard apply to the complete Data
Arrangement. As defined in Section 3, Data Arrangements are suitable for interfacing directly with the PSTN.
Figure Al-1 shows only a typical Data Arrangement and is not representative of all items shown in the figure.
FigureA1-1 shows that the bounds of a Data Arrangement are:
a)
Network interfaces).
b) Unregistered data terminal equipment (DTE) interfaces).
c)
Plug or other provision for connections) to commercial power.
d) Exposed surfaces.
A Data Arrangement may not include all items shown in Figure Al-1. A Data Arrangement may also include
additional items to those shown in this figure. Items contained in a Data Arrangement may be for one integral unit or
may be in physically separate units inter-connected with cords or cables (or by other means) which are themselves
items of the Data Arrangement. Figure Al-2 illustrates some examples of Data Arrangements that might be found in
practice; many others may exist. However, regardless of the form of or physical entities contained, as stated in
Section 3, a Data Arrangement includes all equipment that may affect the pertinent characteristics at the interface.
Equipment or a combination of equipment that does not include all equipment entities that can affect characteristics
at the interface is only part of a Data Arrangement but such equipment shall be considered to conform to this
standard if:
a)
the excluded equipment would connect to a port on the equipment in question,
b) the equipment or combination of equipment complies with all of the applicable requirements in this
standard including those for Equipment-to Equipment interfaces (3) as stated in Sections 4.6-2.2.2, 4.6.3.,
4.6.4., etc. and
c)
A.l.1
associated documentation includes the requirements that excluded equipment must meet at the Equipmentto-Equipment interfaces) to assure that the Data Arrangement will comply with the requirements in this
standard.
Ports
Ports of concern to this standard are Equipment-to-Equipment interfaces of Data Arrangement units which have
Network Interfaces. The Equipment-to-Equipment interfaces of concern are those from which there is, in one or
more operating states of the equipment, a through transmission path to a Network Interface.
A.l.1.1 Port, "Unprotected"
An Unprotected equipment port is one that provides no protection to any Network Interface to which a through
transmission path can exist from equipment connected to the port. An example would be a port, on data
communication equipment, for the connection of a telephone to provide for network control signaling and/or analternate voice capability. The telephone (as with any equipment connected to an unprotected port) must be
registered in accordance with Part 68 of the FCC's Rules.
A.l.1.2 Port, "Fully Protected"
A Fully protected port is one in which any Network Interface, to which a through transmission path can exist, is
protected against hazardous voltages (see 4.9.2.2 and D.5) and excessive voice frequency longitudinal voltages (see
4.6.4). Protection of the Network Interface against calls that may result in improper billing may also be included.
3
Equipment-to-Equipment interface requirements are not applicable in a consideration of the compliance of a
complete Data Arrangement.
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However, the Network Interface(s) are not protected against excessive in-band or out-of-band signal power. Any
DCE connected to such a "Fully Protected" port must be registered in accordance with Part 68.
1 Equipment-to-Equipment interface requirements are not applicable in a consideration of the compliance of a
complete Data Arrangement.
A.l.1.3 Port, "Level Protected"
A Level Protected port is one for which any Network Interface, to which a through transmission path can exist, is
protected as a Fully Protected port. In addition, it is protected against excessive in-band signal power and, if
automatic answer capabilities are involved, is protected against short calls which could result in improper billing (see
Section 4.6.2.5.2). However, Network Interfaces of concern are not protected against excessive out-of-band signal
power from connected equipment or signals which may interfere with the proper operation of billing equipment
through interference with Single Frequency arrangements (see Section 4.6.2.4).
Notes:
1.
A data Arrangement might include: modem, Automatic calling unit, Voice communications device, e.g.
Telephone set, Interconnecting cords and Cables, Host Terminal.
2.
Connection to unregistered Data Terminal Equipment (DTE) may conform to an EIA standard such as
RS 232 or RS 449 depending on the intended use; such conformance is independent of this standard.
Typical Data Arrangement
Figure A.1-1
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Data Arrangement Examples
Figure A.1-2a
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Data Arrangement Examples
Figure A.1-2b
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Data Arrangement Examples
Figure A.1-2c
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A.2
Registered Jacks
The jacks described in this Appendix have been selected from Part 68 as examples of those that might be
encountered in data communications.
In the examples given, each jack is described under its Universal Service Order Code (USOC) number. The reader
will note that this number not only defines the mechanical configuration, but also specifies the electrical connections
to the jack.
A.2.1
RJ11C (Common Reference – Voice Jack)
Single line jack for use with non-key telephones and ancillary devices and for use with permissive Data
Arrangements.
Mechanical Configuration: Six position miniature jack.
Wiring Diagram:
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A.2.2
RJ16X (Common Reference – Voice Jack)
Single line bridged tip and ring with mode indication to a series connection ahead of the bridged connection. For use
with permissive data equipment with Mode Indication (MI) and Mode Indication Common (MIC) leads.
Mechanical Configuration: Six position miniature jack.
Wiring Diagram:
Note: MI and MIC leads are typically wired to an RJ36X series jack which can be used to connect an
exclusion key telephone set ahead of the data arrangement.
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A.2.3 RJ26X (Common Reference – 50 pin Universal Data Jack)
Single or Multiple Line bridged tip and ring for use with either Fixed Loss Loop (FFL) or Programmed types of Data
Arrangement. This jack has no provision for MI or MIC leads.
Mechanical Configuration: 50 contact “ribbon” jack.
Line
T
R
T
R
PR
PC
1
26
1
27
2
28
3
2
29
4
30
5
31
6
3
32
7
33
8
34
9
4
35
10
36
11
37
12
5
38
13
39
14
40
15
6
41
16
42
17
43
18
7
44
19
45
20
46
21
8
47
22
48
23
49
24
Note: At the time the jack is ordered, the customer shall specify the number of and sequence of central office
lines to be connected to the jack. The Telephone Company will consecutively wire these lines to the jack in
accordance with the table above without skipping any positions.
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A.2.4
RJ36X (Common Reference – Voice Jack)
Series tip and ring with mode indication to station behind series connection. For use with exclusion key telephone
set (having MI leads) in series with jack for data equipment.
Mechanical Configuration: miniature 8-position series jack.
Wiring Diagram:
A.2.5
Data Jacks
The eight-position keyed jacks shown on the following pages are designed for use with programmed or fixed loss
loop data equipment. However, the six-position plug of permissive data equipment is designed to properly mate with
these jacks and therefore permissive data equipment may use them as well.
1.
In the fixed loss loop configuration the power delivered to the network is adjusted by means of an attenuator
pad. This pad is selected by the telephone company at the time of installation to provide a signal of –12 dBm at
the central office when the output power of the data equipment is limited to –4 dBm.
2.
In the programmed configuration a programmed resistor in the jack controls the power delivered to the network.
Though this resistor controls the power, it is not in series with it. Therefore the transmitted and received signals
experience no attenuation from the jack. The proper programming resistor (R P) shall be selected by the
telephone company at the time of installation to provide a signal of –12 dBm at the central office based upon the
loop loss of the telephone line. See Section 4.6.2.2.1.
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A.2.6
Programming Resistor Calculation
The circuit shown below was used in calculating values of the programming resistors of Figure 4.6.2-2 and may be
useful in implementing the automatic control of signal power output in the programmed data equipment.
R1 is the source impedance for the input signal Vin and also the terminating impedance of the load. RS is series
resistance that the computation of the programming resistor Rp is based. The values of Rp in figure 4.6.2-2 are
derived for R1 = 600 ohms and Rs = 3600 ohms.
A.2.7
RJ41S (Common Reference – Universal Data Jack)
Single line bridged tip and ring for use with either fixed loss loop or programmed types of data equipment. This jack
may also be used in conjunction with RJ36X for use with an exclusion key telephone to be used ahead of the data
equipment.
Mechanical Configuration: miniature 8-position keyed jack.
Wiring Diagram:
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A.2.8
RJ45S (Common Reference – Programming Data Jack)
Single line bridged tip and ring for use with programmed types of data equipment. This jack may also be used in
conjunction with RJ36X for use with an exclusion key telephone to be used ahead of the data equipment.
Mechanical Configuration: miniature 8-position keyed jack.
Wiring Diagram:
ANNEX B Ringer Equivalence Number (REN)
The affected requirements specified in the Technical Requirements Section of this standard are, as indicated, for an
REN of 1.0. For Data Arrangements having an REN different than 1.0, the applicable requirement is obtained by
scaling the stated requirement as follows:
Z1
ZREN = -------------REN + 0.05
Where: ZREN is the impedance limit specified for the REN of the particular Data Arrangement,
Z1 is the impedance limit specified for an REN of 1, and
REN is the REN of the particular Data Arrangement.
Several requirements, particularly those concerning on-hook impedance, are dependent upon the Ringer Equivalence
Number (REN) of the Data Arrangement. REN is defined in Section 3.23. It is important to recognize that while
REN is derived from ringer equivalence, it is actually a means of allocating the acceptable loading with respect to
several parameters of all entities at the Network Interface. The purpose here is to illustrate, with some sample
calculations, the significance of the REN of a Data Arrangement and how the REN determines the limit on certain
impedance parameters.
REN can be any value from 0.0 to 5.0 in increments of 0.1. In addition, the sum of the REN's of all equipment
entities which bridge a telephone line may not exceed 5.0 and therefore, if an equipment entity (e.g., Data
Arrangement) has an REN of 5.0, it can be connected to a line only if there are no other entities (except those having
an REN of 0.0) connected to that line. Entities having an REN of 4.0 or less can generally be connected to a line
which has one telephone (telephones usually have an REN of 1.0) connected.
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The limit of a particular parameter for a given REN is determined by dividing the nominal value of that parameter
having an REN of 1.0 by the given REN. Since rounding of the REN to the nearest 0.1 is required, the limiting value
of a parameter for a given REN is actually determined by adding 0.05 to the given REN, then dividing, or
multiplying as required, and rounding appropriately. For example, the nominal value of dc resistance, tip to ring, for
voltages up to 100 V (Section 4.1.1.) is 25 megohm. The limit for an REN of 2.3 determined by:
25 megohms
----------------- = 10.7 megohms
2.35
The limit for an REN of 0.0 is determined by:
25 megohms
-----------------= 500 megohms
0.05
Paragraphs 4.1.1 and 4.1.2.1 are required by FCC Part 68. Paragraphs 4.1.2.3, 4.1.2.4, 4.1.4, and 4.2.2 are not
required by Part 68. They are required to insure proper operation of the Data Arrangement.
Figure B-1 illustrates how design limits for a Data Arrangement can be established for a chosen REN with examples
of scaling for five selected values of REN. The limit for any parameter for any value of REN between 0.0 and 5.0 in
steps of 0.1 may be similarly determined.
Conversely, the number in the right hand column can be divided by the measured result on a Data Arrangement to
determine the REN for that parameter.
The minimum REN is determined by the largest of the numbers resulting from a series of calculations. Part 68
requires this number to be based upon four (4) tests of a representative unit. In order to meet the requirements for
minimum acceptable performance, the number must be chosen from the largest resulting REN of the eight (8)
calculations described in this Appendix.
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REN
Section Number
0.0
0.1
0.5
1.0
5.0
4.1.1 Applied
dc Voltage up to
100 V
500
megohms
167
megohms
45.5
megohms
23.9
megohms
4.96
megohms
Divide 25 megohms by
desired (REN +0.5)
4.1.1 Applied
dc Voltage up to
100 to 200 V
3.0
megohms
1.0
megohms
273K
ohms
143K
ohms
29.8K
ohms
Divide 150K ohms by
desired (REN + 0.5)
4.1.2.1 Max
total dc current
0.03 mA
0.09 mA
0.33 mA
0.63 mA
3.03 mA
160K
ohms
53.4K
ohms
14.6K
ohms
7.62K
ohms
1.59K
ohms
4.1.2.1
4.1.2.3
Divide min. impedance of
Figure 4.1.2-1 for Ringer
Type desired (REN + 0.5)
Divide impedance of Figure
4.1.2-1 and Figure 4.1.2-2
by desired (REN + 0.5)
Graph Value / REN
Divide impedance of Figure
4.1.2-5 by desired (REN +
0.5)
(Graph Value) (REN)
Multiply admittance shown
on graph in Figure 4.1.2-4
by desired (REN + 0.06)
4.1.2.4
2.0
megohms
Multiply 0.6 mA by desired
(REN + 0.05)
Graph Value / REN
4.1.2.4
4.1.3.1
Calculated for limit of REN
667K
ohms
182K
ohms
95.3K
ohms
19.9K
ohms
Divide 100K ohms by
desired (REN + 0.05)
Limiting Values of Impedance Parameters for REN
Figure B-1
ANNEX C Physical and Environmental Stresses
The specifications of the physical environmental stresses are provided in Part 68 and are reproduced in this
Appendix. Equipment included within the Data Arrangement that are to be registered in accordance with Part 68 are
required to comply with the electrical requirements of Part 68 both before and after being subjected to these stresses.
It is desirable that Data Arrangements comply with the requirements specified in Section 4.1 through 4.6 and in
Section 4.9 of this standard after being subjected to these stresses.
C.1
Drop Stresses (Normal)
Drop stresses are specified below for each weight class and apply to each unit of equipment that makes up the Data
Arrangement. Impact and test surfaces shall be chosen such that they are perpendicular to the direction of motion of
the unit at the time of impact. These tests are to be performed as follows:

Face Drop
The unit is dropped such that the face struck is approximately parallel to the impact surface.

Corner Drop
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The unit is dropped such that upon impact a line from the struck comer to the center of gravity of the packaged
equipment is approximately perpendicular to the impact surface.

Edgewise Drop
The unit is positioned on a horizontal flat test surface. One edge of the rest face is supported with a block so that the
rest face makes an angle of 200 with the horizontal. The opposite edge is lifted the designated height above the test
surface and dropped.

Cornerwise Drop
The unit is positioned on a horizontal flat test surface. One comer of the rest face is supported with a block so that
the rest face makes an angle of 200 with the horizontal. The opposite comer is lifted the designated height above the
test surface and dropped.

Random Drop
The unit is positioned prior to release to ensure as nearly as possible that for every six drops there is one impact on
each of the six major surfaces and that the surface to be struck is approximately parallel to the impact surface.
C.1.1 Drop Stresses - Equipment Unpackaged
C.1.1.1 Customer Hand-Held Items Normally Used at Head height
a)
This equipment design stress is intended for those equipment items, such as telephone handsets, which are
normally hand-held by the customer at head height.
b) Eighteen random drops from a height of 60 inches (152 cm) onto concrete covered with 1/8 of an inch (0.3-cm)
of asphalt tile or similar surface.
C.1.1.2 Normally Customer Carried Equipment
a)
This equipment design stress is intended for those units of equipment, such as a separate telephone set or
auxiliary unit, which are normally customer carried in repositioning or relocating the units.
b) Six random drops from a height of 30 inches (76 cm) onto concrete covered with 1/8 of an inch (0.3-cm) of
asphalt tile or similar surface.
C.1.2
a)
Equipment Not Normally Customer Carried
This equipment design stress is intended for those units of equipment, which make up the Data Arrangement,
which are not normally customer carried.
b) These stresses are those resulting from impact onto concrete covered with 1/8 of an inch (0.3-cm) of asphalt tile
or similar surface.
i) Equipment Weight of 0 - 20 lb. (0-9 kg):
One 6 inch (15 cm) face drop on each normal or designated rest face, one 3 inch (8 cm) face drop on all other
faces, and one 3 inch (8 cm) comer drop on each comer.
ii) Equipment Weight of 20 - 50 lb. (9-23 kg):
One 4 inch (10 cm) face drop on each normal or designated rest face, one 2 inch (5 cm) face drop on all other
faces, one 2 inch (5 cm) comer drop on each comer.
iii)
Equipment Weight of 50 - 100 lb. (23-45 kg):
One 2 inch (5 cm) face drop on each normal or designated rest face. One edgewise drop and one Cornerwise
drop form a height of 2 inches (5 cm) on each edge and comer adjacent to the rest face.
iv)
Equipment Weight of 100 - 1000 lb. (45-450 kg):
One 1 inch (2.5 cm) face drop on each normal or designated rest face. One edgewise drop and one corner wise
drop from a height of 1-inch (2.5 cm) on each edge and corner adjacent to the rest face.
v)
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Equipment Weight of Over 1000 lb. (Over 450 kg):
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One 1-inch face drop on each normal or designated rest face. One edgewise drop from a height of 1 inch on
each edge adjacent to this rest face.
C.2
Vibration - Transportation Environment (Normal)
The following sinusoidal vibration in simulation of transportation vibration is applied to each unit of equipment,
packaged for shipment and unpackaged, once in each of three orthogonal directions. One frequency sweep is at a
level of 0.5-g peak from 5 to 100 Hz and one sweep at a level of 1.5-g peak from 100 to 500 Hz. The 5 to 100 Hz
sweep is conducted at a sweep rate of 0.1 octave/minute (approximately 45 minute) and the 100 to 500 Hz sweep at a
rate of 0.25 octave/minute (approximately 10 minute).
For equipment packaged for shipment and unpackaged, which designate a specified rest surface, the unit shall be
subjected to the above vibration only while resting on that designated surface.
C.3
Temperature and Humidity Cycle
Cycling at any convenient rate through the following temperature and humidity conditions three times: 30 minutes at
150°F and 15 percent relative humidity, followed by 30 minutes at 90°F and 90 percent relative humidity, followed
by 30 minutes at -40°F and any convenient humidity.
ANNEX D Abbreviated Testing Procedures
D.1
General
To assist designers in satisfying the requirements of Section 4.9, this Appendix describes industry-proven techniques
that produce a high degree of assurance of such compliance. Other techniques that achieve equivalent results may be
used.
Note: The test methods and values described in this Appendix may not include all tests and/or parameters
specified in Part 68. Before taking advantage of these abbreviated procedures, the reader should be
thoroughly acquainted with the complete tests required for rigorous proof of compliance. If any tests or
specifications in this Appendix conflict with or differ from the specifications of Part 68, the tests specified or
implied in Part 68 shall be used.
When the design techniques of this Appendix are followed, it has been found that compliance with the requirements
in Section 4.9.1.2. “Faults on Equipment Interface Leads” is assured when the following test is successfully
performed on a single sample of the Data Arrangement:
A 60 Hz voltage of 106 to 127 Vrms (for a Data Arrangement) or 270 to 330 Vrms (for Fully or Level Protected
ports) applied between all applicable terminals or leads simultaneously, (excluding any interface ground reference)
and ground with the Data Arrangement on the off-hook state, if applicable, and with the interface ground reference
strapped to green wire ground, if such an option is included.
Note: Part 68 requires, for an independent protective circuit, that additional leads be stressed.
D.2
Grounding Metal Chassis
Except as noted below, if a unit of the Data Arrangement connects directly to commercial ac power, or if it connects
to a source of voltage that exceeds 70 volts peak as its chassis shall be securely connected to green wire ground such
that it is grounded whenever the ac power or voltage source is connected. In addition, all exposed conducting
(metal) surfaces that are not removable parts of an equipment enclosure shall be securely grounded. However, the
chassis of an equipment unit that is powered by a physically separate power supply or through a physically separate
power transformer may be ungrounded but the voltages on the connecting leads must not exceed 42.4 volts peak ac
or 80 Vdc.
D.3
Overload Protection
If equipment within the Data Arrangement connects to commercial power, it shall include overload protection. The
required protection shall involve one or more of the following:
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a)
Series resistance (e.g., transformer winding resistance) high enough to limit the current to a level that will
not cause overheating of any element,
b) A saturable-core reactor or similar magnetic control of short circuit current,
c)
A thermal cut-out which shall not automatically reset if additional fusing is not used,
d) A fuse, or
e)
A circuit breaker
The rating of fuses and circuit breakers shall not exceed the current carrying capacity of the wire in their circuits. In
addition, wiring external to equipment housings shall meet the requirements of Article 725 of National Electric
Code.
D.4
Connection and Wiring
D.4.1
Physical Separation
a)
Leads to, or any elements having a conducting path to telephone connections or auxiliary leads shall:
i)
Be reasonably physically separated and restrained from, and be neither routed in the same cable as nor use
the same connector as leads or metallic paths connecting to commercial power connections;
ii) Be reasonably physically separated and restrained from, and be neither routed in the same cable as nor use
adjacent pins on the same connector as metallic paths or leads connecting to Data Terminal Equipment
(DTE) interface terminals if the interface voltages exceed 42.4 volts peak ac or 80 Vdc.
b) Regardless of Data Terminal Equipment (DTE) interface voltages, leads having a conducting path to tip or ring
terminals, in any operating states of the equipment, shall not use pins or terminals on a connector, terminal
block, or terminal field if such pins or terminals are adjacent to pins or terminals used by leads or metallic paths
to Data Terminal Equipment (DTE) interface terminals or to any element having a conducting path to ground
unless the pins or terminals meet at least one of the following:
i)
Pins or terminals (including spade tip lead connections) with a conducting path to a tip or ring terminal are
sleeved or prevented by a nonconductive spare or other construction feature from being shorted to an
adjacent pin or terminal.
ii) Pins or terminals and adjacent pins or terminals have sufficient spacing or rigidity that an applied force of 5
lb. (2.25 kg) to a pin or terminal will not result in its making electrical contact with another. (It shall be
assumed that the screw holding a spade tip cannot be tightened to make the connection sufficiently rigid.)
In addition, the means of restraint to maintain the alignment of wires in a cable that includes wires with a conductive
path to tip or ring terminal shall be such that individual wire insulation will not be cut during manufacture, operation
or repair.
All wiring and cabling shall be routed clear of sharp edges and hot spots.
D.4.2
Power Cords
Cords for connection to commercial power and their attachment shall meet the requirements of the National Electric
Code, Article 400 (Flexible cords and cables). The cord should be protected with a suitable strain bushing where it
enters the equipment capable of supporting a load of 35 lb. (1 6 kg) or twice the weight of the equipment unit,
whichever is less, applied to the cord. Ends of removable cords that may contain live terminals shall have female
connectors.
D.4.3
Bushings
Except as noted below, insulating bushings or some other means of restraining wires from contacting the edge of an
opening in metal within an equipment shall be used if such wires, in any operating mode of the Data Arrangement,
are in any of the following categories:
a)
Wires which connect to commercial power,
b) Wires which connect or have a conductive path to a source of voltages which exceeds 70 volts peak, or
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c)
Wires which connect or have a conductive path to the tip and/or ring terminals
However, when the edges of the opening are smooth and rounded with a radius of least 1/32 of an inch (0.08 cm),
neither bushings nor other means of restraint are required for category b) wires or for category c) wires, specified
above.
D.5
Dielectrics
With the Data Arrangement in any possible operating state, a 60 Hz voltage is applied (except as noted below)
between points on the equipment, enumerated below (points a-f), in the combinations listed in Figure D-5. The
voltage is gradually increased from zero to the maximum value given in the table over a 30-second time interval, and
then applied continuously for 1 minute. The current in the mesh formed by the voltage source and the points on the
equipment, enumerated below, shall not exceed 10-mA peak at any time during this 90-second time interval.
a)
All exposed surfaces (exclusive of securely grounded metal surfaces) of the Data Arrangement
b) Terminals, phase and neutral, for connection to commercial ac power
c)
Tip and Ring Interface terminals
d) Data Terminal Equipment (DTE) terminals and terminals of a Fully or Level Protected port
e)
Point(s) having a conducting path to the secondary(s) of any power supply which connects to commercial ac
power
f)
Terminals for connection to green wire ground
Maximum
Voltage
Combination
Points
(Volts rms)
(1)
from (a) to (b) & (d)
1500
(2)
from (a) to (c) & (e)
1000
(3)
from (b) to (c), (d), (e) & (f)
1500
(4)
from (c) to (d) & (f)
1000
COMBINATIONS OF ELECTRICAL CONNECTIONS FOR
DIELECTRIC BREAKDOWN EVALUATION
FIGURE D-5
Referring to Figure D-5, the limitations apply as follows:
1.
For combinations (1) and (2), compliance with the requirement shall be considered to be assured for conductive
exposed surfaces which are not securely grounded by either:
(a) (a)Verifying that all conductive exposed surfaces, which are not securely grounded, are separated from (and
restrained from contacting) all elements or components of the equipment by an air gap or solid dielectric at
least 0.062 inch (0. 16 cm) thick, or
(b) (b)Verifying compliance with the requirements when all conductive exposed surfaces, which are not
securely grounded, are insulated for test purposes at all points of possible contact to securely grounded
equipment parts.
2.
For combination (3), if in any operating state of the Data Arrangement there is an intentional conducting path
(internal or external) from point (b) to a terminal(s) included in point (d), the requirement is not applicable from
point (b) to the point (d) terminal(s) involved.
3.
If the equipment includes a voltage source that exceeds 70 volts peak breakdown shall not occur with up to 1500
Vrms-is at 60 Hz applied from point (e) to points (a) or (c). The ground reference of (e) shall be connected to
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point (f) and such connection shall be capable of carrying current four times greater than the capability of the
high voltage source.
4.
For Data Arrangements consisting of multiple-unit equipment interconnected by cables, the specified 10 ma
peak maximum leakage current limitation, other than between terminals for connection to commercial power and
other points, may be increased as desired herein to accommodate cable capacitance. The leakage current
limitation may be increased to (10N + 0.04L) ma peak, where L is the length of interconnecting cable in the
leakage path in feet, and N is the number of equipment units which the Data Arrangement will place in parallel
across the tip and ring of the Network Interface. However, all combinations of electrical connections requiring
this increased leakage current limitation and involving (a) surfaces (exposed surfaces) must comply with the
requirements in Section 4.9.1.3, Fault on Exposed Conductive Surfaces, in addition to other applicable
requirements.
Compliance with these criteria shall be considered to be assured if there is a dielectric barrier with the required
strength between the points specified. For example, dielectric breakdown shall not be considered to specified. For
example, dielectric breakdown shall not be considered to occur between any two points if the peak current limit
would not be exceeded with any series element(s) short-circuited.
D.6
Fault Isolation Circuitry
1.
General requirements for the isolation of faults on Data Terminal Equipment (DTE) leads are specified in
Section 4.9.1.2. However, compliance can be assured for all possible applications of the hazardous voltage by a
relatively few elements that can be evaluated as specified below and, if necessary, tested independently.
2.
If the requirement specified in D.5, combination (4), for the tip and ring interface leads is applicable in at least
one operating state, then any physical elements (e.g., transformer) that provide a transmission path(s) through
such dielectric barriers, together with specified associated components, shall assure that the voltage appearing
between the tip and ring terminals or between either terminal and ground, with a 1500 ohm resistive load
connected between tip and ring with a centertap connected to ground through a 1000 ohm resistor, does not
exceed 42.5 volts peak for more than I second after a 60 Hz voltage of up to 300 Vrms is applied between any
two points at the Data Terminal Equipment (DTE) interface of such circuitry. In addition, the Data
Arrangement shall comply with the dielectric requirements in D.5 subsequent to the removal of the above
specified 60 Hz potential. The Data Terminal Equipment (DTE) interface of such circuitry shall include all
conductive paths to other circuitry on the unregistered equipment side of the dielectric(s) providing compliance
with D.5.
3. There is no restriction on the number of elements that may be included in the circuitry defined as providing the
required protection nor on the number of conducting paths in the interface of such circuitry with other circuitry.
However, for all elements included, the characteristics relevant to achieving compliance with this requirement shall
be specified as part of the individual component specification, e.g., if compliance depends upon a particular resistor
acting as a fuse, its relevant fusing characteristics shall be included in the specification.
ANNEX E Network Signaling Weighting Functions
E.1
Protection against Transmission Interruptions
The following criteria, defined in terms of the configuration in Figure El-1, apply throughout the entire duration of a
call for all signals which the Data Arrangement may generate or may be caused to generate (e.g., by any digital
sequence), and for all intended applications and modes of operation. The configuration in Figure El-1, which is
applicable to disconnect-prevention criteria, is also applicable to the transmission-interruption criteria with the value
of the R2 C2 time constant changed to 15 milliseconds. Frequency weighting functions for the three applicable
signal-band filters are defined in Figures El-4, El-5, and El-6. The frequency weighting functions for the two
applicable guard filters are defined in Figure El-2 (the same filter as used in the disconnect-prevention criteria) and
Figure El-7. The output voltage V0(t) of the configuration, for all filter combinations as specified below, should not
exceed zero for any sequence of signals. The output voltage V0(t) requirements shall be met using the following
three filter combinations:
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Condition
Signal-Band Filter
Guard-Band Filters
1
Figure E1-4
Figure E1-2
2
Figure E1-5
Figure E1-2
3
Figure E1-6
Figure E1-7
Signaling Interface Test Arrangement
FIGURE E1-1
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Guard Band Weighting Function
FIGURE E1-2
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Signal Band Weighting Function
FIGURE E1-3
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Signal Band Weighting Function
FIGURE E1-4
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Signal Band Weighting Function
FIGURE E1-5
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Signal Band Weighting Function
FIGURE E1-6
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Guard Band Weighting Function
FIGURE E1-7
ANNEX F Electrical Environmental Stresses
Data Arrangements shall comply with the requirements in Section 4.1 through 4.6 and in Appendix G after being
subjected to the following environmental stresses designated as normal. In addition, it is desirable for Data
Arrangements to continue to comply with the requirements in Appendix G after being subjected to the stresses
designated below as abnormal.
F.1
Normal Telephone Line Potentials and Currents
F.l.1
Permanent Signal Release Test (Normal)
Data Arrangements that remain off-hook for more than 10 seconds after the far-end station disconnects may be
subjected to a permanent release test voltage. If such Data Arrangements do not comply with the loop interrupt
disconnect provision specified in Section 4.5.2, it may be subjected to a loop battery source of ± 52.5 Vdc, with a
source resistance of 10 ohms, applied to the tip and ring of the Network Interface for 0.5 second.
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F.1.2
Switchboard Operation (Normal)
Calls which involve operator assistance may be connected to loop battery source in parallel resulting in the
application of ± 56.5 Vdc, with an effective resistance of 165 ohms, applied to the tip and ring of the Network
Interface for 1 second. This stress applies to the Data Arrangement in the Voice Mode.
F.2
Ground Path Current Surges (Abnormal)
A Data Arrangement, having more than one external connection to ground, may be subjected to very high current
surges between such connections as a result of lightning strikes on commercial power lines or telephone lines. Such
multiple connections provide alternative paths to ground for surge currents.
Ground path current surges can exist between any of the following possible external connections to ground (only if
such surges are not isolated by a dielectric capable of withstanding 1000 Vrms at 60 Hz for 60 s, without
breakdown):
1) Green wire ground (including any interface connection point that may be connected to green wire ground
through other equipment or connection points). However, the existence of more than one direct or indirect
connection to green wire ground does not constitute multiple external connections to ground for the purpose of
determining the potential for ground current surges.
2) Connections to protector block ground
3) Any connection to a conductive structural member of a building, a metal water pipe or ground stake.
These ground path surges can be of either polarity and can have current amplitudes of up to 2000 amps peak, rise
time as short as 4 microseconds and decay times as long as 160 microseconds.
The Data Arrangement is subjected to these surges between each of the different external connections of any of the
three types of paths to ground. For example, if the Data Arrangement has a connection to protector ground and also
has a connection to green wire ground through the power supply and through other equipment, the surges apply
between each of the green wire ground connections individually and the protector block ground connection.
F.3
Transients
Values in the following paragraphs are offered only for guidance.
F.3.1
Surges Associated with Protectors
These surges are representative of those occurring with properly grounded, operational protectors. The surges
specified here are not representative of those resulting from direct lightning strikes nor improperly grounded
protectors (See Figure F.3-1). All surges are applicable in all possible operating states of the Data Arrangement with
any of the possible terminations (which may provide a conducting path for surge related currents) on interface
connection points to other equipment. This section defines both "normal" and "abnormal" surges. The surges are
specified in Figure F.3-1.
1)
Type P Surges
Type P surges are applied to power leads between the phase conductor and neutral conductor with green wire ground
connected to the neutral conductor, and between neutral conductor and phase conductor with green wire ground
connected to the phase conductor. Type P surges are applicable in all possible states in which the Data Arrangement
connects to power. With respect to surge P2, compliance with the requirements in Appendix D.5 is not significant
provided that following the application of such a surge, the voltage on tip and ring leads, or between tip or ring and
ground, does not exceed 70 volts peak for more than 1 second with tip and ring interfaces terminated 1500 ohms
center-tapped to ground through 1000 ohms.
2)
Type M Surges
Type M surges are applicable to the tip and ring of the Network Interface leads and are applicable with and without
ungrounded exposed conductive surfaces treated as ground reference (connected to green wire ground). Type M
surges occur between a pair of tip/ring leads with each lead of each pair individually connected to green wire ground
(if such a ground connection, direct or indirect, exists). Type M surges can strike all possible combinations of the tip
and ring of the Network Interface leads simultaneously, but with the same polarities with respect to ground.
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3)
Type L Surges
Type L surges are applicable to all tip and ring of the Network Interface leads and are applicable with and without
ungrounded exposed conductive surfaces treated as a ground reference (connected to green wire ground). Type L
surges occur between the tip and ring of the Network Interface connection points connected together and green wire
ground. Type L surges can strike all possible combinations of the interface leads simultaneously, but with the same
polarities with respect to ground.
Type Ll, L2 and L3 surges are applicable under all reasonable foreseeable possibilities of disconnection of
connections of such equipment with primary commercial power (e.g., without any associated plug ended primary
power cord connected). Also, the Type Ll, L2 and L3 surges are applicable with only the third wire ground
connection in a primary power source plug disconnected. In these cases, the surges are applicable with source
reference being the ground reference of interface lead terminations which could, in service, have a path for surge
currents to green wire ground.
NUMBER
PEAK
PEAK
TYPE
AMPLITUDE
(V)
AVAILABLE
(1)
(2)
CURRENT
(A)
MAXIMUM
MINIMUM
of SURGES
RISE
DECAY
OF EACH
(3)(5)
TIME
(us)
(4)(5)
TIME
(us)
POLARITY
P1 (normal)
2500
1000
2
10
4
P2 (abnormal)
5000
1000
2
10
1
Ml (normal)
600
100
10
1000
4
M2 (normal)
800
100
10
560
2
M3 (abnormal)
600
100
10
2500
1
M4 (abnormal)
1000
200
10
1000
1
L1 (normal)
600
200
10
1000
4
L2 (normal)
1000
200
10
360
2
L3 (normal)
1500
200
10
160
2
L4 (abnormal)
600
200
10
2500
1
L5 (abnormal)
1500
400
10
1000
1
(1) Peak Amplitude - is the peak surge voltage with the source terminated in 10 kilohms.
(2) Peak Available Current - is the peak current that the surge voltage source can deliver into a short circuit.
(3) Maximum Rise Time - is the time interval between the 10 percent and 90 percent of peak points, on the
leading edge, multiplied by 1.25.
(4) Minimum Decay Time - is the time interval between the 10 percent of peak point on the leading edge and
the 50 percent of peak point on the trailing edge.
(5) Rise and Decay Time apply to voltage waveforms measured into an open circuit and to the waveform of the
current that flows through a short circuit.
SURGE DESCRIPTION
FIGURE F.3-1
The number of surges specified in Figure F.3-1 is not necessarily adequate to assure any particular service life for a
Data Arrangement. For this reason, it is desirable that the Data Arrangement withstands a number of surges
considerably in excess of those specified.
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F.3.2
Transient Voltages during Call Setup (Normal)
During call set-up when loop current is interrupted, e.g., during dial pulse opens and disconnect (calls abandoned
during the address signaling stage), high inductance relays in some central offices create transients. The maximum
transient voltages that can occur across an opening, protected, contact in the equipment are given in Figure F.3-2 as a
function of the contact protection capacitance.
F.4
Power Line Faults and Line Crosses (Abnormal)
Under power line fault conditions or when metallic contact between commercial power conductors and telephone
cables occurs, protectors normally limit potentials appearing between the tip and ring conductors or to ground, to
less than 600 Vrms. In most cases, power system fault detectors or telephone line protectors will limit the duration
of such voltages to a few seconds. However, they may last indefinitely, therefore a protector should not provide a
short to ground under these conditions.
Time in Milliseconds after Contact Opens
Transient Voltage across Contacts for Different Values of
Contact Protection Capacitance
FIGURE F3-2
66
Copyright 1998 TIA - All Rights ReservedWorking Draft
Draft 1 PN 4256 September 9, 1998
ANNEX G Electrical Hazard Prevention
G.1
Maximum Voltages and Currents - Fault Conditions
The following requirements apply with both the 60 Hz source used to power units of the Data Arrangement that
connect to commercial power and any applied voltage sources having the capability of delivering at least 20 A
continuously and 50 A for at least one minute. For Data Arrangements that connect to commercial power, the
ground reference shall be green wire ground and, if a ground reference is included in Data Terminal Equipment
(DTE) interface terminals to which voltages are applied, the requirement below applies with and without such
ground reference connected to green wire ground. The requirements apply in all operating states and modes of the
Data Arrangement.
Appendix D contains information to assist designers in satisfying the requirements of this section.
As a result of equipment failure the Data Arrangement shall not apply a voltage, at points V1, V2, and V3, exceeding
42.5 volts peak for more than 1 second as shown in Figure G-1.
Conditions:
1) Fault in Data Arrangement
2) Fault on Equipment Interface Leads.
A fault condition of a 60 Hz voltage of up to 120 Vrms applied between any combination of DTE terminals
and/or between any such interface terminal and ground.
A fault condition of a 60 Hz voltage of up to 300 Vrms applied between any combination of terminals of a
fully or level protected port and/or between any such interface terminal and ground.
3) Fault on exposed conductive surfaces.
A fault condition of a 60 Hz voltage of 120 Vrms applied between conductive exposed surfaces and ground.
TEST CONDITION FOR MAXIMUM VOLTAGE
DURING FAULT CONDITION
FIGURE G-1
Copyright 1998 TIA - All Rights ReservedWorking Draft
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Draft 1 PN 4256 September 9, 1998
ANNEX H Related Documents
ANSI Standards:
Tl.401 - 1988
Interface between carriers and customer installations.
AT&T Publications:
43801
Digital Channel Bank Requirements and Objectives.
47001
Electrical characteristics of the Bell System network facilities at the interface with
voiceband ancillary and data equipment.
47002
Key system telephone.
Communication:
Canada
CS03 Issue 6
Standard for terminal equipment, systems, network protection devices and
connection arrangements.
EIA Standards:
EIA - 470-A
Telephone instruments with loop signaling.
RS - 464
PBX switching equipment for voiceband applications.
FCC Rules:
Part 68
A compilation of FCC rules for registration of telephone equipment.
IEEE Standards:
743
IEEE standard methods of measuring longitudinal balance.
455
IEEE standard methods and equipment for measuring the transmission characteristics
of analog voice frequency circuits.
68
Copyright 1998 TIA - All Rights ReservedWorking Draft