SIST TBR 002 E1:2004

• Abstract:

  Technical characteristics of packet mode terminal equipment capable of connection to a dedicated interface of a packet switched public data network using CCITT Recommendation X.25, making use of LAPB and LAPB extended

• Status: Published
• Publication Date: 30-Sep-2004
• ICS: 33.040.40 - Data communication networks
• Technical Committee: SPS - Signalling protocols and switching
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Oct-2004
• Due Date: 01-Oct-2004
• Completion Date: 01-Oct-2004
• Mandate: T-237B
• Ref Project: ETSI TBR 002 ed.1 (1997-01) - Digital Terminals and Access (DTA); Attachment requirements for Data Terminal Equipment (DTE) to connect to Packet Switched Public Data Networks (PSPDNs) for CCITT Recommendation X.25 interfaces at data signalling rates up to 1 920 kbit/s utilizing interfaces derived from CCITT Recommendations X.21 and X.21 bis

SIST TBR 002 E1:2004 is the Slovenian standard corresponding to ETSI TBR 2 Edition 1. It specifies attachment requirements for Data Terminal Equipment (DTE) that connects to Packet Switched Public Data Networks (PSPDNs) through CCITT Recommendation X.25 interfaces at data signalling rates up to 1 920 kbit/s, using interfaces derived from CCITT Recommendations X.21 and X.21 bis.

The document is aimed at equipment makers, test laboratories, and approval bodies that need a common basis for connector, electrical, and access-control testing at the public network boundary. Its focus is the interface to the network, not end-to-end terminal operation across networks.

What does SIST TBR 002 E1:2004 specify?

SIST TBR 002 E1:2004 specifies the technical characteristics for packet mode terminal equipment intended for connection to a dedicated PSPDN interface. It covers electrical and mechanical interface requirements and the access control protocol to be provided, with the stated objective of protecting the public network and enabling interworking at the interface.

The standard is organized into seven clauses:

• scope
• normative references
• definitions and abbreviations
• modes of operation and signalling rates
• safety and EMC requirements
• electrical, mechanical, and access control protocol requirements
• TBR test specification

Annex	What it covers
Annex A	TBR Requirements Table, including requirement status and connector/contact assignment tables
Annex B	PIXIT proforma for test-specific implementation information
Annex C	Explanatory note, including the purpose of TBR 2 and its relationship to NET 2
Annex D	Bibliography

What are the key requirements of SIST TBR 002 E1:2004?

SIST TBR 002 E1:2004 is mainly a Layer 1 interface standard with connector, electrical, and test requirements. It does not set X.25 link-layer or packet-layer performance requirements, so the document is about attachment behavior rather than protocol conformance.

Interface scope and boundary

• Clause 4 limits the standard to packet mode terminal equipment at data signalling rates up to and including 1 920 kbit/s. In practice, this tells a buyer or designer whether the product family falls inside the approval basis.
• Clause 6 says the requirements apply at the means of connection to the DCE. That matters because the tests are performed at the public network interface, not inside the equipment.
• Clause 6.1 defines balanced and unbalanced generator and receiver presentations using test points A, B, C and A', B', C'. Those reference points are the basis for the voltage and timing measurements used in the tests.

Connector options and pin assignments

• Clause 6.2 allows five connector styles: 25-pole, 26-pole, 37-pole, 34-pole, and 15-pole. Annex A gives the matching contact-number assignments for each case.
• The pin assignments depend on which interchange circuits the DTE actually implements. For a manufacturer, this means the declared interface type must match the exact connector and circuit list in Annex A.
• For the 15-pole option, Annex A notes that only one of the timing-related options may be implemented and active at the same time. This is important when configuring a product that offers multiple timing functions.

Electrical characteristics

• Clause 6.3 sets different electrical requirements for interchange circuits intended for CCITT Recommendation V.10, V.11, V.28, and V.35. In practice, you test only the set that matches the presented interface.
• For generator outputs, the document checks open-circuit voltage, terminated output voltage, and rise time or transition time, depending on the interface family. These checks confirm that the DTE drives the line within the limits expected by the DCE.
• For V.28 receivers, Clause 6.3 also sets a maximum effective shunt capacitance. That matters because excessive capacitance can slow signals and affect interoperability.
• Clause 6.3 also states the required polarity relationship for binary 0 and binary 1, or ON and OFF for control circuits. This prevents reversed signalling at the network boundary.
• The requirements apply only to generator states that are relevant to the actual implementation. If a generator is fixed in one state, only that state is tested, and Annex B records such cases.

Test method and evidence

• Clause 7 sets the test environment to 15 °C to 35 °C and 5 % to 75 % relative humidity, with tests performed in the power-on condition. That gives laboratories a common testing basis.
• Tests are normally carried out at the highest declared signalling rate for which approval is sought. This matters because it checks the equipment at its most demanding operating point.
• Clause 7.1.9 allows electrical characteristics to be verified either by the prescribed tests or, by agreement, by a declaration of conformance supported by circuit diagrams and component specifications. That gives a documented route when direct measurement is not the only practical option.
• Annex A and Clause 7.7 work together to select the right test cases from the implementation’s declared connector and interface choices. In other words, the product’s own declarations drive the test plan.

What terms does SIST TBR 002 E1:2004 define?

• Data Terminal Equipment (DTE) - The terminal equipment that connects to the DCE at the public network interface.
• Data Circuit Terminating Equipment (DCE) - The network-side terminating equipment presented by the public data network.
• Packet Switched Public Data Network (PSPDN) - A packet-switched public network intended for the X.25 interface described by the standard.
• Link Access Procedure Balanced (Modulo 8 operation) (LAPB) - The balanced link-layer mode named in the scope for packet-mode operation.
• LAPB Extended (Modulo 128 operation) - The extended balanced link-layer mode named in the scope for packet-mode operation.
• PIXIT - Physical layer implementation extra information for testing, recorded in Annex B to support test preparation.
• TBR-RT - The TBR Requirements Table, which summarizes requirements and is used to choose test cases.
• IUT - Implementation Under Test, the equipment or configuration being checked in the test setup.

Who uses SIST TBR 002 E1:2004?

SIST TBR 002 E1:2004 is used by DTE manufacturers, interface designers, and compliance engineers who need to design the public network connection correctly. Test laboratories use it to build the right setups, choose the correct annex tables, and measure the required voltages, timing, and connector assignments.

It is also used by quality managers, approval bodies, and buyers who need to confirm that a terminal supports the declared connector type and interface family. For procurement, the key practical questions are: which connector is used, which interchange circuits are implemented, and which test group applies.

Which standards are used with SIST TBR 002 E1:2004?

• CCITT Recommendation X.25 [1]-[3] - Defines the packet-mode DTE/DCE interface that the standard is built around.
• CCITT Recommendation X.2 [4]-[5] - Provides the service classes and optional user facilities mentioned in the scope and definitions.
• CCITT Recommendation X.21bis [6] and X.21 [7] - Provide the related access-interface basis used for the connector and attachment requirements.
• ISO 2110 [8], ISO/IEC 11569 [9], ISO 4902 [10], ISO 2593 [11], ISO 4903 [12] - Define the connector types and contact-number assignments used in Annex A.
• CCITT Recommendation X.200 [13] - Provides the OSI basic reference model used to describe the layer boundary of the terminal equipment.
• TBR 1 - Is used in the introduction as the comparison document for the related physical-layer requirements.

What does the SIST TBR 002 E1:2004 document contain?

The document contains the requirement tables, pin assignments, and test descriptions needed to assess a packet-mode DTE against the interface rules. Annex A is especially important because it maps each connector option to the required and optional circuits and links those choices to the test-case selection expressions.

The test specification includes measurement setups for open-circuit voltage, terminated voltage, rise time or transition time, and receiver shunt capacitance. It also includes the test case index and the Boolean selection expressions used to decide which tests apply to a given implementation.

Annex B adds implementation-specific information for testing, such as fixed-state generators, identically implemented circuits, and the declared signalling-rate range. Annex C explains the background to the standard, including its relation to NET 2, while Annex D lists the supporting bibliography.

SLOVENSKI STANDARD
01-oktober-2004
'LJLWDOQLWHUPLQDOLLQGRVWRS'7$3ULNOMXþLWYHQH]DKWHYH]DSRGDWNRYQR
WHUPLQDOVNRRSUHPR'7(]DSULNOMXþHYDQMHQDSDNHWQRNRPXWLUDQDMDYQD
SRGDWNRYQDRPUHåMD363'1V]DYPHVQLNHSRSULSRURþLOX&&,77;V
SRGDWNRYQLPLVLJQDOL]DFLMVNLPLKLWURVWPLGRNELWVNLXSRUDEOMDMRYPHVQLNH
SRSULSRURþLOLK&&,77;LQ;ELV
Digital Terminals and Access (DTA); Attachment requirements for Data Terminal
Equipment (DTE) to connect to Packet Switched Public Data Networks (PSPDNs) for
CCITT Recommendation X.25 interfaces at data signalling rates up to 1 920 kbit/s
utilizing interfaces derived from CCITT Recommendations X.21 and X.21 bis
Ta slovenski standard je istoveten z: TBR 002 Edition 1
ICS:
33.040.40 Podatkovna komunikacijska Data communication
omrežja networks
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL TBR 2
BASIS for January 1997
REGULATION
Source: ETSI TC-TE Reference: DTBR/TE-005002
ICS: 33.020, 33.040.40
Key words: PDN, testing, type approval, X.25
Attachment requirements for Data Terminal Equipment (DTE)
to connect to Packet Switched Public Data Networks (PSPDNs)
for CCITT Recommendation X.25 interfaces at
data signalling rates up to 1 920 kbit/s
utilizing interfaces derived from
CCITT Recommendations X.21 and X.21 bis
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: [e-mail]
Tel.: [phone] - Fax: [phone]
Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1997. All rights reserved.

Page 2
TBR 2: January 1997
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

Page 3
TBR 2: January 1997
Contents
Foreword .7
Introduction.7
1 Scope .9
2 Normative references.10
3 Definitions and abbreviations .11
3.1 Definitions .11
3.2 Abbreviations .11
4 Modes of operation and signalling rates.11
4.1 Types of operation .11
4.2 Data signalling rate .11
5 Safety and EMC requirements .11
5.1 Safety requirements.11
5.2 EMC requirements.11
6 Electrical, mechanical, and access control protocol requirements .12
6.1 General characteristics .12
6.1.1 Generator presentations.12
6.1.1.1 Balanced generator .12
6.1.1.2 Unbalanced generator .12
6.1.2 Receiver presentations.12
6.1.2.1 Balanced receiver.12
6.1.2.2 Unbalanced receiver.12
6.2 Connector characteristics and contact number assignments.12
6.2.1 Attachment to a DCE interface presented on a 25-pole connector.12
6.2.1.1 Connector .12
6.2.1.2 Contact number assignments.12
6.2.2 Attachment to a DCE interface presented on a 26-pole connector.13
6.2.2.1 Connector .13
6.2.2.2 Contact number assignments.13
6.2.3 Attachment to a DCE interface presented on a 37-pole connector.13
6.2.3.1 Connector .13
6.2.3.2 Contact number assignments.13
6.2.4 Attachment to a DCE interface presented on a 34-pole connector.13
6.2.4.1 Connector .13
6.2.4.2 Contact number assignments.14
6.2.5 Attachment to a DCE interface presented on a 15-pole connector.14
6.2.5.1 Connector .14
6.2.5.2 Contact number assignments.14
6.3 Electrical requirements .14
6.3.1 Requirements for attachment to CCITT Recommendation V.10
interchange circuits .15
6.3.1.1 Generator open circuit output voltage.15
6.3.1.2 Generator terminated output voltage.15
6.3.1.3 Generator output rise time.16
6.3.1.4 Generator polarities .16
6.3.2 Requirements for attachment to CCITT Recommendation V.11
interchange circuits .17
6.3.2.1 Generator open circuit output voltage.17
6.3.2.2 Generator terminated output voltage.17
6.3.2.3 Generator output rise time.18
6.3.2.4 Generator polarities .19

Page 4
TBR 2: January 1997
6.3.3 Requirements for attachment to CCITT V.28 interchange circuits. 19
6.3.3.1 Generator open circuit output voltage. 20
6.3.3.2 Generator terminated output voltage . 20
6.3.3.3 Generator output signal transition time . 21
6.3.3.4 Generator polarities. 22
6.3.3.5 Receiver maximum effective shunt capacitance. 22
6.3.4 Requirements for attachment to CCITT Recommendation V.35
interchange circuits. 22
6.3.4.1 Generator open circuit output voltage. 22
6.3.4.2 Generator terminated output voltage . 23
6.3.4.3 Generator output rise time . 23
6.3.4.4 Generator polarities. 24
6.4 X.25 link layer (layer 2) requirements. 24
6.5 X.25 packet layer (layer 3) requirements . 24
7 TBR Test Specification . 25
7.1 Conditions of test. 25
7.1.1 Environment for tests. 25
7.1.2 Power supply limitations . 25
7.1.3 Test condition . 25
7.1.4 Test point. 25
7.1.5 Bit patterns. 25
7.1.6 Signal element timing . 25
7.1.7 Data signalling rates . 25
7.1.8 Interchange circuits presentation. 26
7.1.9 Physical layer tests . 26
7.1.9.1 Verification of the electrical characteristics. 26
7.1.9.2 Identically implemented circuits . 26
7.1.9.3 Fixed state generators . 26
7.2 Test descriptions for connector characteristics and contact number assignments . 26
7.2.1 25-pole connector. 26
7.2.1.1 Connector characteristics . 26
7.2.1.2 Contact number assignments . 26
7.2.2 26-pole connector. 26
7.2.2.1 Connector characteristics . 26
7.2.2.2 Contact number assignments . 27
7.2.2.2.1 Connection to a DCE presenting
CCITT Recommendation V.10 or V.11
electrical characteristics. 27
7.2.2.2.2 Connection to a DCE presenting
CCITT Recommendation V.28
electrical characteristics. 27
7.2.3 37-pole connector. 27
7.2.3.1 Connector characteristics . 27
7.2.3.2 Contact number assignments . 27
7.2.4 34-pole connector. 27
7.2.4.1 Connector characteristics . 27
7.2.4.2 Contact number assignments . 27
7.2.5 15-pole connector. 28
7.2.5.1 Connector characteristics . 28
7.2.5.2 Contact number assignments . 28
7.3 Test descriptions for attachment to CCITT V.10 interchange circuits. 28
7.3.1 Generator characteristics . 28
7.3.1.1 Generator open circuit output voltage. 28
7.3.1.2 Generator terminated output voltage . 29
7.3.1.3 Generator output rise time . 30
7.4 Test descriptions for attachment to CCITT Recommendation V.11 interchange circuits . 31
7.4.1 Generator characteristics . 31
7.4.1.1 Generator open circuit output voltage. 31
7.4.1.2 Generator terminated output voltage . 32
7.4.1.3 Generator output rise time . 33
7.5 Test descriptions for attachment to CCITT V.28 interchange circuits. 34
7.5.1 Generator characteristics . 34

Page 5
TBR 2: January 1997
7.5.1.1 Generator open circuit output voltage.34
7.5.1.2 Generator terminated output voltage.35
7.5.1.3 Generator output signal transition time.36
7.5.2 Receiver characteristics .37
7.5.2.1 Receiver effective shunt capacitance.37
7.6 Test descriptions for attachment to CCITT Recommendation V.35 interchange circuits.37
7.6.1 Generator characteristics .37
7.6.1.1 Generator open circuit output voltage.37
7.6.1.2 Generator terminated output voltage.39
7.6.1.3 Generator output rise time.40
7.7 TBR 2 Test Case Selection Expression Definition table.41
7.8 Test case Index .42
Annex A (normative): The TBR Requirements Table (TBR-RT).43
A.1 Introduction to the TBR-RT .43
A.2 Format of the tables .43
A.3 Notations used in the TBR-RT .44
A.3.1 Status notations .44
A.3.2 Support answer notations .44
A.4 The TBR Requirement Tables .45
A.4.1 Connection to a DCE presenting an ISO 2110 [8] (25-pole) connector.45
A.4.2 Connection to a DCE presenting an ISO/IEC 11569 (26-pole) connector.46
A.4.3 Connection to a DCE presenting an ISO 4902 (37-pole) connector.50
A.4.4 Connection to a DCE presenting an ISO 2593 (34-pole) connector.52
A.4.5 Connection to a DCE presenting an ISO 4903 [12] (15-pole) connector.55
Annex B (normative): Physical layer implementation extra information for testing (PIXIT).57
Annex C (informative): Explanatory note to TBR .58
C.1 Purpose of TBR 2.58
C.2 Title and scope.58
C.3 Relationship to NET 2 .58
C.4 NET to TBR conversion process.58
C.5 Means of connection to the DCE.58
Annex D (informative): Bibliography.59
History.60

Page 6
TBR 2: January 1997
Blank page
Page 7
TBR 2: January 1997
Foreword
This Technical Basis for Regulation (TBR) has been produced by the Terminal Equipment (TE) Technical
Committee of the European Telecommunication Standards Institute (ETSI).
Introduction
The physical layer requirements contained in this TBR are a superset of the physical layer requirements
contained in TBR 1 (see annex D), which relate to the connection of a terminal to a Circuit Switched Public
Data Network (CSPDN) using CCITT Recommendation X.21 [7]. It is recommended that a demonstration
of compliance with these requirements be accepted as a demonstration of compliance with the relevant
parts of TBR 1 for the purpose of determining conformity with that TBR, and vice versa.

Page 8
TBR 2: January 1997
Blank page
Page 9
TBR 2: January 1997
1 Scope
This Technical Basis for Regulation (TBR) specifies the technical characteristics (electrical and
mechanical interface requirements) and access control protocol to be provided by packet mode terminal
equipment intended for connection to a dedicated interface of a Packet Switched Public Data Network
(PSPDN) using CCITT Recommendation X.25 [1], [2] and [3] making use of Link Access Procedure
Balanced (Modulo 8 operation) (LAPB) and Link Access Procedure Balanced (Modulo 128 operation)
(LAPB Extended) modes of operation.
The objective of this TBR is to ensure that no disturbance occurs to the public network, and to ensure
interworking between network and terminal, but without any guarantee of terminal operation and end to
end operability across networks.
This TBR contains the minimum set of requirements derived from CCITT Recommendation X.25 [1], [2]
and [3] in accordance with prior European harmonization documents (NET 2, see annex D). The
requirements of this TBR are suitable for testing terminal equipment for connection to
CCITT Recommendation X.25 [1], [2] and [3] (1980, 1984, and 1988) PSPDNs. Terminal equipment that
is capable of either originating only or terminating only, packet level modes of operation have been
included. Data Terminal Equipment (DTE) which satisfies the relevant technical requirements of this TBR
may be connected to every PSPDN, use any of the essential (E) facilities and invoke any of the provided
additional (A) facilities as given in CCITT Recommendation X.2 [4] and [5].
For each requirement in this TBR, a test is given, including measurement methods. Requirements apply
at the public network interface of the terminal equipment, which may be stimulated to perform tests by
additional equipment if necessary. For the purposes of this TBR a terminal equipment comprises of that
apparatus included between a PSPDN Network Termination Point (Data Circuit Terminating Equipment
(DCE)), and the terminal equipment boundary point that delimits the Network to Transport layers as
defined in ITU-T (CCITT Recommendation X.200) subclause 7.5 (Reference model of Open Systems
Interconnection). Equipment in this context is taken to mean either software, firmware or hardware.
Where the packet mode terminal equipment supplied for test does not contain the functions of layers 1, 2
and 3 (as defined in ITU-T (CCITT Recommendation X.200) subclause 7.5 (Reference model of Open
Systems Interconnection)), the terminal's documentation and instructions for use shall state which
additional equipment is required for compliance to this TBR and the additional equipment shall be
submitted for test, as though all the functional layers were provided by the packet terminal equipment.
This TBR also gives guidance on appropriate standards relating to the essential requirements on safety.
Terminal equipment may be subject to additional or alternative attachment requirements in other CTRs
depending on its functionality, in particular if it supports a service which is considered a justified case for
regulation of terminal equipment interworking via the public telecommunications network.

Page 10
TBR 2: January 1997
2 Normative references
This TBR incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications are
to apply to this TBR only when incorporated in it by amendment or revision. For undated references the
latest edition of the publication referred to applies.
[1] CCITT Recommendation X.25 (1980): "Interface between Data Terminal
Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals
operating in the packet mode and connected to public data networks by
dedicated circuit".
[2] CCITT Recommendation X.25 (1984): "Interface between Data Terminal
Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals
operating in the packet mode and connected to public data networks by
dedicated circuit".
[3] CCITT Recommendation X.25 (1988): "Interface between Data Terminal
Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals
operating in the packet mode and connected to public data networks by
dedicated circuit".
[4] CCITT Recommendation X.2 (1984): "International data transmission services
and optional user facilities in public data networks".
[5] CCITT Recommendation X.2 (1988): "International data transmission services
and optional user facilities in public data networks and ISDNs".
[6] CCITT Recommendation X.21bis (1988): "Use on public data networks of data
terminal equipment (DTE) which is designed for interfacing to synchronous
V-series modems".
[7] CCITT Recommendation X.21 (1988): "Interface between data terminal
equipment (DTE) and data circuit-terminating equipment (DCE) for synchronous
operation on public data networks".
[8] ISO 2110 (1980): "Information Technology - Data communication - 25-pole
DTE/DCE interface connector and contact number assignments".
[9] ISO/IEC 11569 (1992): "Information Technology - Telecommunications and
information exchange between systems - 26-pole interface connector
mateability dimensions and contact number assignments".
[10] ISO 4902 (1980): "Information Technology - Data communication - 37-pole
DTE/DCE interface connector and contact number assignments".
[11] ISO 2593 (1984): "Information Technology - Telecommunications and
information exchange between systems - 34-pole DTE/DCE interface connector
and contact number assignments".
[12] ISO 4903 Second edition (1989): "Information Technology - Data
communication - 15-pole DTE/DCE interface connector and contact number
assignments".
[13] CCITT Recommendation X.200: "Information technology - Open Systems
Interconnection - Basic reference model: The basic model".

Page 11
TBR 2: January 1997
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this TBR, the following definitions apply:
CCITT recommendation X.25 [1] to [3] network: A PSPDN network which offers a
CCITT Recommendation X.25 [1], [2] and [3] DTE/DCE interface providing the (E) facilities for user
classes of service 8-11 as defined in CCITT Recommendation X.2, [4] and [5].
All other definitions are as given in the CCITT series of Recommendations.
3.2 Abbreviations
For the purposes of this TBR, the following abbreviations apply:
CL total effective capacitance associated with the load, measured at the
interchange point
DCE Data Circuit Terminating Equipment
DTE Data Terminal Equipment
EMC Electro-Magnetic Compatibility
hex hexadecimal
IUT Implementation Under Test
LAPB Link Access Procedure Balanced (Modulo 8 operation)
LAPB Extended Link Access Procedure Balanced (Modulo 128 operation)
PIXIT Protocol Implementation Extra Information For Testing
PSPDN Packet Switched Public Data Network
RL total effective resistance associated with the load, measured at the interchange
point
TBR-RT TBR Requirements Table
Vo open-circuit generator voltage
4 Modes of operation and signalling rates
4.1 Types of operation
This TBR is applicable to packet mode terminal equipment intended for connection to a dedicated
interface of a packet switched public data network.
NOTE: The requirements contained in this TBR may be suitable for terminal equipment
intended for connection to a public data network interface using
CCITT Recommendations X.21 [6] or X.21bis [7] interfaces that is not a PSPDN.
4.2 Data signalling rate
This TBR is applicable for packet mode terminal equipment operating at data signalling rates up to and
including 1 920 kbit/s (User Class 59 of CCITT Recommendation X.1, see annex D).
5 Safety and EMC requirements
5.1 Safety requirements
There are no safety requirements under this TBR.
NOTE: Safety requirements are imposed under the Low Voltage Directive (73/23/EEC) and
articles 4 (a) and 4 (b) of Directive 91/263/EEC.
5.2 EMC requirements
There are no EMC requirements under this TBR.

Page 12
TBR 2: January 1997
NOTE: General EMC requirements are imposed under EMC Directive (89/336/EEC).
6 Electrical, mechanical, and access control protocol requirements
The requirements of this clause apply at the means of connection to the DCE.
6.1 General characteristics
6.1.1 Generator presentations
6.1.1.1 Balanced generator
In the case of balanced terminal equipment generators, points A and B are defined as the two physical
connections, on the means provided for connection to the DCE, to which the output of a terminal
generator is connected, and point C is the physical connection on the means of connection to the DCE to
which the terminal equipment signal ground may optionally be connected (see figure 5).
6.1.1.2 Unbalanced generator
In the case of unbalanced terminal equipment generators, point A is defined as the physical connection on
the means provided for connection to the DCE, to which the output of a terminal generator is connected,
and point C is the physical connection on the means of connection to the DCE to which the signal ground
associated with that generator is connected.
6.1.2 Receiver presentations
6.1.2.1 Balanced receiver
In the case of balanced terminal equipment receivers, points A' and B' are defined as the two physical
connections, on the means provided for connection to the DCE, to which the input of a terminal receiver is
connected, and point C' is the physical connection on the means of connection to the DCE to which the
terminal equipment signal ground may optionally be connected.
6.1.2.2 Unbalanced receiver
In the case of unbalanced terminal equipment receivers, point A' is defined as the physical connection on
the means provided for connection to the DCE, to which the input of a terminal receiver is connected, and
point C' is the physical connection on the means of connection to the DCE to which the signal ground
associated with that generator is connected.
6.2 Connector characteristics and contact number assignments
The means of connection to the DCE shall conform to either subclause 6.2.1, 6.2.2, 6.2.3 ,6.2.4 or 6.2.5.
6.2.1 Attachment to a DCE interface presented on a 25-pole connector
6.2.1.1 Connector
The means of connection to the DCE shall be a male connector conforming to ISO 2110 [8].
NOTE: This requirement is based upon subclause 1.2 of CCITT Recommendation X.21 bis [6].
Compliance shall be checked by the test given in subclause 7.2.1.1.
Justification: Directive 91/263/EEC, article 4 (d).
6.2.1.2 Contact number assignments
On the means of connection to the DCE, the presentation of the interchange circuits shall be in
accordance with annex A, tables A.1 and A.2 or tables A.5 and A.6.

Page 13
TBR 2: January 1997
NOTE: This requirement is based upon subclause 1.2 of CCITT Recommendation X.21 bis [6]
and ISO 2110 [8].
Compliance shall be checked as described in subclause 7.2.1.2.
Justification: Directive 91/263/EEC, article 4 (d).
6.2.2 Attachment to a DCE interface presented on a 26-pole connector
6.2.2.1 Connector
The means of connection to the DCE shall be a male connector conforming to ISO/IEC 11569 [9].
NOTE: This requirement is based upon ISO/IEC 11569 [9].
Compliance shall be checked by the test given in subclause 7.2.2.1 as appropriate.
Justification: Directive 91/263/EEC, article 4 (d).
6.2.2.2 Contact number assignments
On the means of connection to the DCE, the presentation of the interchange circuits shall be in
accordance with annex A, tables A.5 and A.6 or tables A.9 and A.10.
NOTE: This requirement is based upon ISO/IEC 11569 [9].
Compliance shall be checked as described in subclause 7.2.2.2 as appropriate.
Justification: Directive 91/263/EEC, article 4 (d).
6.2.3 Attachment to a DCE interface presented on a 37-pole connector
6.2.3.1 Connector
The means of connection to the DCE shall be a male connector conforming to ISO 4902 [10].
NOTE: This requirement is based upon subclause 1.2 of CCITT Recommendation
X.21 bis [6].
Compliance shall be checked by the test given in subclause 7.2.3.1 as appropriate.
Justification: Directive 91/263/EEC, article 4 (d).
6.2.3.2 Contact number assignments
On the means of connection to the DCE, the presentation of the interchange circuits shall be in
accordance with annex A, tables A.13 and A.14.
NOTE: This requirement is based upon subclause 1.2 of CCITT Recommendation X.21 bis [6]
and ISO 4902 [10].
Compliance shall be checked as described in subclause 7.2.3.2 as appropriate.
Justification: Directive 91/263/EEC, article 4 (d).
6.2.4 Attachment to a DCE interface presented on a 34-pole connector
6.2.4.1 Connector
The means of connection to the DCE shall be a male connector conforming to ISO 2593 [11].

Page 14
TBR 2: January 1997
NOTE: This requirement is based upon subclause 1.2 of CCITT Recommendation
X.21 bis [6].
Compliance shall be checked by the test given in subclause 7.2.4.1 as appropriate.
Justification: Directive 91/263/EEC, article 4 (d).
6.2.4.2 Contact number assignments
On the means of connection to the DCE, the presentation of the interchange circuits shall be in
accordance with annex A, tables A.17 and A.18.
NOTE: This requirement is based upon subclause 1.2 of CCITT Recommendation X.21 bis [6]
and ISO 2593 [11].
Compliance shall be checked as described in subclause 7.2.4.2 as appropriate.
Justification: Directive 91/263/EEC, article 4 (d).
6.2.5 Attachment to a DCE interface presented on a 15-pole connector
6.2.5.1 Connector
The means of connection to the DCE shall be a male connector conforming to ISO 4903 [12].
NOTE: This requirement is based upon subclause 2.2 of CCITT Recommendation X.21 [7].
Compliance shall be checked by the test given in subclause 7.2.5.1 as appropriate.
Justification: Directive 91/263/EEC, article 4 (d).
6.2.5.2 Contact number assignments
On the means of connection to the DCE, the presentation of the interchange circuits shall be in
accordance with annex A, tables A.24 and A.25.
NOTE: This requirement is based upon subclause 2.2 of CCITT Recommendation X.21 [7]
and ISO 4903 [12].
Compliance shall be checked as described in subclause 7.2.5.2 as appropriate.
Justification: Directive 91/263/EEC, article 4 (d).
6.3 Electrical requirements
For a particular terminal implementation, the generator requirements of this TBR apply only to the extent
that they are relevant to a particular generator. For instance, where, in a particular terminal
implementation, a particular generator circuit, in normal operation, is fixed in one of the binary states, only
those requirements relevant to that fixed binary state shall apply.
NOTE: It is possible for particular interchange circuits of a TE to be intended for connection to
more than one type of interchange circuit which could be presented by a DCE (e.g. to
both CCITT Recommendations V.10 and V.28, see annex D).
Where an interchange circuit, presented by the TE, to which a particular section of
subclause 6.3 applies, is intended to be connected additionally to interchange circuits
presented by a DCE which conform to other sections of subclause 6.3, the
requirements of that section of subclause 6.3 relevant to those characteristics also
apply.
Page 15
TBR 2: January 1997
Additionally, for a particular DTE-DCE interface, not all signals may be employing the
same interchange circuit characteristics. It is the interchange characteristic of the
individual signals presented by the network that dictate which sections of
subclause 6.3 apply.
6.3.1 Requirements for attachment to CCITT Recommendation V.10 interchange circuits
The requirements of this subclause apply to interchange circuits, presented by the TE on the means for
connection to the DCE, that are intended for connection to circuits presented by the DCE that conform to
CCITT Recommendation V.10 (see annex D).
6.3.1.1 Generator open circuit output voltage
When a 3 900 Ω non-reactive impedance is connected between points A and C, for each binary state, the
magnitude of the voltage between points A and C shall be less than or equal to 12,0 V.
A
G
IVoI <= 12,0V
R Vo
R = 3 900 Ω
C
NOTE: This requirement is based upon CCITT Recommendation V.10 subclauses 5.2.1 and 6.3 (see
annex D).
Figure 1
Compliance shall be verified in accordance with the test specified in subclause 7.3.1.1.
Justification: Directive 91/263/EEC, article 4d.
6.3.1.2 Generator terminated output voltage
The magnitude of the output voltage, for either binary state, of a generator when terminated with a 450 Ω
non-reactive impedance connected between points A and C shall be greater than or equal to 2,0 V.
A
G
IVtI >= 2,0 V
R Vt
R = 450 Ω
C
NOTE: This requirement is based upon CCITT Recommendation V.10 subclause 5.2.2 (see annex D).
Figure 2
Page 16
TBR 2: January 1997
Compliance shall be verified in accordance with the test specified in subclause 7.3.1.2.
Justification: Directive 91/263/EEC, article 4f.
6.3.1.3 Generator output rise time
During transitions from one binary state to another, the time taken for the differential voltage measured
between points A and C to pass between the points at which, for each binary state, it is 90 % of its steady
state value, shall be less than or equal to 0,3 of the nominal duration of a bit. For the purposes of this
requirement, transient signals are ignored. (see figure 4).
This requirement applies when the output of the generator is connected to the circuit shown in figure 3.
A
G
R = 450 Ω
V (t)
R
t
C
Figure 3
t
b
0,1Vss
V
ss
0,1Vss
t
t
r+ r-
Vss=Voltage difference between steady-state signal conditions;
tb=nominal duration of a bit. For tb ≥ 50μs, tr ≤ 0,3 tb.
NOTE: This requirement is based upon CCITT Recommendation V.10 subclause 5.3 (see annex D).
Figure 4
Compliance shall be verified in accordance with the test specified in subclause 7.3.1.3.
Justification: Directive 91/263/EEC, article 4f.
6.3.1.4 Generator polarities
The generator output voltage at point A shall be:
a) positive with respect to point C when the signal condition 0 (space) for data circuits, or ON for
control circuits, is transmitted; and

Page 17
TBR 2: January 1997
b) negative with respect to point C when the signal condition 1 (mark) for data circuits, or OFF for
control circuits, is transmitted.
Compliance shall be checked with the tests described in subclause 7.3.1.2.
6.3.2 Requirements for attachment to CCITT Recommendation V.11 interchange
circuits
The requirements of this subclause apply to interchange circuits, presented by the TE on the means for
connection to the DCE, intended for connection to circuits presented by the DCE that conform to CCITT
Recommendation V.11 (see annex D).
6.3.2.1 Generator open circuit output voltage
When a 3 900 Ω non-reactive impedance is connected between points A and B, for each binary state (see
figure 5):
a) the magnitude of the voltage between points A and B shall be less than or equal to 12,0 V;
b) The magnitude of the voltage between either points A or B and point C shall be less than or equal to
12,0 V.
≤ 12,0V
G
12,0V
≤
12,0V
≤
R = 3 900 Ω
NOTE: This requirement is based upon CCITT Recommendation V.11 subclauses 5.2.1 and 6.3 (see
annex D).
Figure 5
Compliance shall be verified in accordance with the test specified in subclause 7.4.1.1.
Justification: Directive 91/263/EEC, article 4d.
6.3.2.2 Generator terminated output voltage
When terminated with two 50 Ω non reactive impedances connected in series between points A and B
(see figure 6):
a) the magnitude of the steady state voltage, for either binary state, shall be greater than or equal to
2,0 V between points A and B; and
b) the magnitude of the steady state voltage, for either binary state, shall be less than or equal to
3,0 V, between the centre point of the two 50 Ω non reactive impedances and point C.

Page 18
TBR 2: January 1997
G
R1 = R2 = 50 Ω
NOTE: This requirement is based upon CCITT Recommendation V.11 subclause 5.2.2 (see annex D).
Figure 6
Compliance shall be verified in accordance with the test specified in subclause 7.4.1.2.
Justification:
Directive 91/263/EEC, article 4f.
6.3.2.3 Generator output rise time
During transitions from one binary state to another, the time taken for the differential voltage measured
between points A and B to pass between the points at which, for each binary state, it is 90 % of its steady
state value, shall be less than or equal to 0,3 of the nominal duration of a bit. For the purposes of this
requirement, transient signals are ignored.(see figure 8).
This requirement applies when the output of the generator is connected to the circuit shown in figure 7.
A
R1
Vt
G
W
R1 = R2 = R3 = 50
R2
B
R1 & R2 =matched
R3
C
Figure 7
Page 19
TBR 2: January 1997
t
b
0,1Vss
V
ss
0,1Vss
t t
r-
r+
Vss=Voltage difference between steady-state signal conditions;
tb=nominal duration of a bit. For tb ≥ 50μs, tr ≤ 0,3 tb.
NOTE: This requirement is based upon CCITT Recommendation V.11 subclause 5.3 (see annex D).
Figure 8
Compliance shall be verified in accordance with the test specified in subclause 7.4.1.3.
Justification: Directive 91/263/EEC, article 4f.
6.3.2.4 Generator polarities
The generator output voltage at point A shall be:
a) positive with respect to point B when the signal condition 0 (space) for data circuits, or ON for
control circuits, is transmitted; and
b) negative with respect to point B when the signal condition 1 (mark) for data circuits, or OFF for
control circuits, is transmitted.
Compliance shall be checked with the tests described in subclause 7.4.1.2.
6.3.3 Requirements for attachment to CCITT V.28 interchange circuits
The requirements of this subclause apply to interchange circuits, presented by the TE on the means for
connection to the DCE, that are intended for connection to circuits presented by the DCE that conform to
CCITT Recommendation V.28 (see annex D).

Page 20
TBR 2: January 1997
6.3.3.1 Generator open circuit output voltage
When connected as shown in figure 9, the magnitude of the voltage between points A and C shall be less
than or equal to 25,0 V.
A
G
|Vo| <=25,0V
Vo
C
NOTE: This requirement is based upon CCITT Recommendation V.28 subclause 4 (see annex D).
Figure 9
Compliance shall be verified in accordance with the test specified in subclause 7.5.1.1.
Justification: Directive 91/263/EEC, article 4d.
6.3.3.2 Generator terminated output voltage
The output voltage for either binary state shall be greater than or equal to 3,0 V, when terminated in a
3 000 Ω non-reactive impedance between generator points A and C (see figure 10).
A
G
IV I >= 3,0V
t
R V
t
R 3 000 Ω
C
NOTE: This requirement is based upon CCITT Recommendation V.28 subclause 4 (see annex D).
Figure 10
Compliance shall be verified in accordance with the test specified in subclause 7.5.1.2.
Justification: Directive 91/263/EEC, article 4f.

Page 21
TBR 2: January 1997
6.3.3.3 Generator output signal transition time
The time required for the generator output voltage to traverse the region between -3,0 V and +3,0 V during
a transition from one binary state to the other shall not exceed 1,0 ms, or 3 % of the nominal duration of a
bit, whichever is the lesser (see figure 12).
This requirement applies when the output of the generator is connected to the circuit shown in figure 11.
A
G
R = 3 000 Ω
(t)
V
R C
t C = 2 500 pF
C
Figure 11
t
b
3,0V
V
0V
Transition Region
ss
-3,0V
t t
r-
r+
Vss=Voltage difference between steady-state signal conditions;
tb=nominal duration of a bit.
NOTE: This requirement is based upon CCITT Recommendation V.28 subclause 6, paragraph 4 (see
annex D).
Figure 12
Compliance shall be verified in accordance with the test specified in subclause 7.5.1.3.
Justification: Directive 91/263/EEC, article 4f.

Page 22
TBR 2: January 1997
6.3.3.4 Generator polarities
The generator output voltage at point A shall be:
a) positive with respect to point C when the signal condition 0 (space) for data circuits, or ON for
control circuits, is transmitted; and
b) negative with respect to point C when the signal condition 1 (mark) for data circuits, or OFF for
control circuits, is transmitted.
Compliance shall be checked with the tests described in subclause 7.5.1.2.
6.3.3.5 Receiver maximum effective shunt capacitance
The total effective shunt capacitance shall be less than or equal to 2 500 pF between the receiver points
A' and C' (see figure 13):
NOTE: This requirement is based upon CCITT Recommendation V.28 subclause 3, fourth paragraph
(see annex D).
Figure 13
Compliance shall be verified in accordance with the test specified in subclause 7.5.2.1.
Justification: Directive 91/263/EEC, article 4f.
6.3.4 Requirements for attachment to CCITT Recommendation V.35 interchange
circuits
The requirements of this subclause apply to interchange circuits, presented by the TE on the means for
connection to the DCE, that are intended for connection to circuits presented by the DCE that conform to
CCITT Recommendation V.35 (see annex
...