ISO 2110-1989 amd1-1991 PDF

Full title and description

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. This document is the 1991 amendment to ISO 2110:1989 introducing contact assignments and an informational annex relevant for higher signalling rates.

Abstract

This amendment updates Clauses 1 and 2 and Table 1 of ISO 2110:1989 and adds an informative Annex B, to specify connector contact number assignments and related notes when the DTE/DCE interface operates at data signalling rates above 20 000 bit/s. It is intended to ensure compatible pin assignments and clarify usage for higher‑speed serial interfaces using the 25‑pole connector form factor.

General information

• Status: Published amendment (definitive as published).
• Publication date: 26 September 1991 (ISO 2110:1989/Amd 1:1991).
• Publisher: International Organization for Standardization (ISO), developed under ISO/IEC JTC 1 (Telecommunications/data exchange).
• ICS / categories: 35.100.10 (Physical layer: data communication).
• Edition / version: Amendment 1 to ISO 2110:1989 (published as ISO 2110:1989/Amd 1:1991).
• Number of pages: 3 (amendment document length).

Scope

This amendment applies to the 25‑pole DTE/DCE interface connector specified in ISO 2110:1989 and covers revised connector/contact assignments and explanatory notes that are specifically required when the interface carries data signalling rates above 20 000 bit/s. It is intended for use where higher signalling rates may affect signal assignment, routing or compatibility with existing V‑series/physical signalling recommendations.

Key topics and requirements

• Revisions to Clauses 1 and 2 of ISO 2110:1989 to clarify applicable conditions for higher signalling rates.
• Changes to Table 1 (contact number assignments) to accommodate signalling above 20 000 bit/s.
• Addition of Annex B (informative) providing guidance and informational material for high‑rate applications.
• Guidance for ensuring compatibility with established serial signalling recommendations (e.g., ITU‑T V‑series) and for modem/PDN applications using the 25‑pole connector form.

Typical use and users

Engineers and designers of serial data interfaces and telecommunications equipment (modems, data terminal equipment, data circuit‑terminating equipment), test laboratories, standards committees, and procurement specialists who need authoritative pin/contact assignments and guidance for 25‑pole DTE/DCE connectors used at signalling rates above 20 kb/s.

Related standards

ISO 2110:1989 (base standard); ITU‑T V‑series recommendations relevant to DTE/DCE signalling (for example V.24 and V.28) and other interface/cable/connector standards that govern serial physical‑layer characteristics and signal levels. National adoptions (e.g., BS ISO 2110, ČSN adoption) typically incorporate the base standard together with this amendment.

Keywords

ISO 2110, 25‑pole connector, DTE/DCE, contact number assignments, amendment 1991, data signalling >20 000 bit/s, serial interface, modem interface, connector pinout.

FAQ

Q: What is this standard?

A: It is Amendment 1 (1991) to ISO 2110:1989, which specifies changes and additions to the 25‑pole DTE/DCE connector contact assignments for higher signalling rates.

Q: What does it cover?

A: It updates specific clauses and the contact assignment table of ISO 2110:1989 and adds an informative annex (Annex B) to address interface and contact assignment requirements when the DTE/DCE link operates above 20 000 bit/s.

Q: Who typically uses it?

A: Telecom and data‑communications hardware designers, modem manufacturers, test laboratories, system integrators and standards bodies that must ensure correct pinouts and interoperability for 25‑pole DTE/DCE physical interfaces at higher serial data rates.

Q: Is it current or superseded?

A: The amendment was published on 26 September 1991 and was issued as ISO 2110:1989/Amd 1:1991. Public listings show the amendment as the published update to the 1989 base standard; users should check their national standards body or the ISO catalog for any later revisions or withdrawals applicable in their country.

Q: Is it part of a series?

A: Yes — it is an amendment to ISO 2110:1989 (the series of documents covering the 25‑pole DTE/DCE connector and assignments). Related ITU‑T/CCITT V‑series recommendations are often referenced for signalling and compatibility.

Q: What are the key keywords?

A: 25‑pole, DTE, DCE, connector, contact assignments, pinout, amendment 1991, high signalling rate, serial interface.