ISO 2110:1989/Amd 1:1991

Information technology — Data communication — 25-pole DTE/DCE interface connector and contact number assignments — Amendment 1: Interface connector and contact number assignments for a DTE/DCE interface for data signalling rates above 20 000 bit/s per second

Includes specific changes to ISO 2110:1989 Clauses 1 and 2, and Table 1. Adds the new Annex B. Annex B is for information only.

Technologies de l'information — Communication de données — Connecteur d'interface ETTD/ETCD à 25 pôles et affectation des numéros de contacts — Amendement 1: Connecteur d'interface et affectation des numéros de contacts à l'interface ETTD/ETCD pour un débit binaire supérieur à 20 kbit/s

General Information

• Status: Published
• Publication Date: 25-Sep-1991
• ICS: 35.100.10 - Physical layer
• Technical Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Drafting Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Current Stage: 6060 - International Standard published
• Start Date: 26-Sep-1991
• Completion Date: 14-Feb-2026

Relations

• Amends: ISO 2110:1989 - Information technology — Data communication — 25-pole DTE/DCE interface connector and contact number assignments
• Effective Date: 06-Jun-2022
• Child: ISO 2110:1989 - Information technology — Data communication — 25-pole DTE/DCE interface connector and contact number assignments
• Effective Date: 15-Apr-2008

Overview

ISO 2110:1989/Amd 1:1991 is an amendment to the international standard for 25-pole DTE/DCE interface connectors, published by the International Organization for Standardization (ISO). This amendment focuses on updating connector and contact number assignments specifically for DTE/DCE interfaces used in data communication environments where data signalling rates exceed 20,000 bits per second. The amendment ensures reliable, high-speed data transmission and compatibility among equipment designed for enhanced data communication requirements.

This amendment introduces specific changes to clauses and tables in the original ISO 2110:1989 document and adds a new informative Annex B. These updates help data communication equipment manufacturers and integrators maintain consistent connector specifications, improve interoperability, and adapt to advancing technologies.

Key Topics

• Connector and Contact Assignments: Updates to the 25-pole DTE/DCE interface connector ensure clear guidelines for contact numbering in high-speed communication scenarios above 20,000 bit/s.
• Electrical Characteristics: Recommends adherence to CCITT (now ITU-T) Recommendations V.10 and V.11 for electrical features, addressing both unbalanced (V.10) and balanced (V.11) circuits for general use in integrated data communication equipment.
• Interoperability Considerations: Notes on compatibility with existing connectors and devices conforming to earlier or alternative recommendations (such as V.28, V.35, V.36, and V.37) to prevent issues during interconnection.
• Adapter Use and Cross-Reference: Annex B provides informative guidance for interoperation between standards-based equipment, including sample circuit diagrams and compatibility notes for integrating various connector types and legacy devices.

Practical Applications

ISO 2110:1989/Amd 1:1991 is particularly valuable for:

• Network Equipment Manufacturers: Ensuring that routers, modems, switches, and related hardware with DTE/DCE interfaces comply with up-to-date connector assignments for high-speed data transmission.
• System Integrators and Installers: Providing clear reference for implementing or upgrading serial communication interfaces in IT, automation, and telecommunications systems.
• Data Communication Engineers: Facilitating troubleshooting and efficient design of systems that interconnect diverse equipment running at high signalling rates.
• Testing and Maintenance: Supporting accurate identification of contacts and electrical expectations, improving device compatibility, signal integrity, and maintenance operations.

The standard is suitable for applications such as wideband modems, enterprise networking, and other environments where fast and reliable serial communication is essential.

Related Standards

To maximize compatibility and interoperability, this amendment references several related international standards and recommendations, including:

• ISO 2110:1989: The original specification for 25-pole DTE/DCE interface connector and contact assignments.
• CCITT/ITU-T Recommendation V.10: Describes electrical characteristics for unbalanced, double-circuit interchange circuits.
• CCITT/ITU-T Recommendation V.11: Specifies electrical characteristics for balanced, double-circuit interchange circuits.
• CCITT/ITU-T Recommendation V.28: Defines electrical characteristics commonly used with earlier 25-pole connectors.
• CCITT/ITU-T Recommendations V.35, V.36, V.37: Handle specific cases for wideband, high-speed, and legacy modem interconnections.
• ISO 4902 and ISO 2593: Related standards referenced for cross-compatibility and connector assignment mapping.

These references enable organizations to ensure full compliance, minimize errors, and support a robust data communication infrastructure.

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Keywords: ISO 2110, DTE/DCE interface, high-speed data communication, 25-pole connector, contact assignment, CCITT V.10, CCITT V.11, data transmission, interoperability, data communication standard, serial communication, network equipment, international standardization.

Standards Content (Sample)

INTERNATIONAL
ISO
STANDARD
Third edition
1989-10-01
AMENDMENT 1
1991-09-15
Information technology - Data
communication
- 25pole DTE/DCE interface
connector and contact number assignments
AMENDMENT 1: Interface connector and contact
assignments for a DTEIDCE interface for data
signalling rates above 20 000 bit/s
Technologies de Rnformation - Communication de donnees - Connecteur
d’interface ETTD/ETCD 3 25 pOles et affectation des numt!ros de contacts
AMENDEMENT 7: Connecteur d’interface et affectation des num&os de contacts &
l’interface ETTD/ETCD pour un d&bit binaire suphieur h 20 kbith
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Reference number
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ISO 2110 : 1989/Amd.l : 1991 (E)
-- .-- --
ISO 2110 : 1989/Amd.l : ‘l991 (EI
Foreword
ISO (the International Organization for Standardization) and IEC (the International
Electrotechnical Commission) form the specialized System for worldwide standardiz-
ation. National bodies that are members of ISO or IEC participate in the development
of International Standards through technical committees established by the respective
organization to deal with particular fields of technical activity. ISO and IEC technical
committees collaborate in fields of mutual interest. Other international organizations,
governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work.
In the field of information technology, ISO and IEC have established a joint technical
committee, ISO/IEC JTC 1. Draft International Standards adopted by the joint
technical committee are circulated to national bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the national bodies casting
a vote.
Amendment 1 to International Standard ISO 2110 : 1989 was prepared by Joint
Technical Committee ISO/IEC JTC 1, lnformation technology.
Annex B of this Amendment is for information only.
0 ISO/IEC 1991
All rights reserved. NO part of this publication may be reproduced or utilized in any form or by any
means, electronie or mechanical, including photocopying and microfilm, without Permission in
writing from the publisher.
ISO/IEC Copyright Office l Case postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
ii
ISO 2110 : 1989/Amd.l : 1991 (E)
Information technology - Data communication - 25-pole
DTE/DCE interface connector and contact number
assignments
AMENDMENT 1 : Interface connector and contact assignments
for a DTEIDCE interface for data signalling rates above
20 000 bit/s
Page 7 Pages 4 and 5
Table 1
Clause 1
Add the following column and add the following notes:
Add the following:
“In the case where Operation exceeding 20 000 bit/s is
required, the electrical characteristics shall be in accordance
with CCITT Recommendation V. 10 and CCITT Recommen-
dation V. 11.”
1)
2 103-A
Clause 2 3 104-A
4 105-A / 133-A
5 106-A
Insert the following after “CCITT Recommendation
6 107’5)
S.16 : 1989”:
7 102-A
109-A
“CCITT Recommendation V. 10 : 1988, Electrical characteristics 115-B
IO 109-B
for unbalanced double-circuit in terchange circuits for general
11 113-B
use with integra ted circuit equipment in the field of data com-
12 114-B
munica tions.
13 106-B
14 103-B
CCITT Recommendation V. 11 : 1988, Electrical characteristics
15 ‘l14-A
for balanced double-circuit in terchange circuits for general use
16 104-B
17 115A
with integra ted circuit equipment in the field of data com-
141’5)
munica tions. ”
19 105-B/133-B
108’5)
m
140’5)
125’5)
102-B
...