Overview
ISO/IEC 11569:1993 defines a 26‑pole connector for use at the DTE/DCE (data terminal equipment / data circuit‑terminating equipment) interface. The standard specifies mateability dimensions and contact number assignments for a shielded 26‑pin connector intended for serial V‑series modem interfaces. It applies where the interface’s functional characteristics conform to CCITT Recommendation V.24 and electrical characteristics conform to V.10, V.11, or V.28. The standard explicitly excludes modems for parallel data transmission. Annex A gives guidance on interoperation with other interfaces (for example ISO 2110 and certain V‑series recommendations).
Key Topics and Requirements
- Connector type and purpose: A shielded 26‑pole connector for the cable (male contacts) and equipment (female contacts) used at the DTE–DCE interface.
- Mateability dimensions: Figures in the standard (Figures 1–4) illustrate essential mating dimensions, seating plane, latching mechanism and housing relationships needed to ensure mechanical and electrical compatibility.
- Contact number assignments: A mapped assignment of contact numbers to interchange circuits (e.g., signal ground/common return, transmitted data, received data, control and status signals such as RTS, DTR, DSR). Table 2 in the standard provides the full mapping and notes about balanced circuit sides (A/B) where applicable.
- Shielding and grounding: The connector is specified as shielded; contact 1 is provided for shield continuity with national grounding rules affecting implementation.
- Scope limits and conditional assignments: Certain contact/circuit assignments are only required for specific modem types or V‑series recommendations (e.g., backward channel circuits or higher‑speed V‑series modems).
Applications and Who Uses It
- Telecommunications equipment manufacturers designing serial modem interfaces and DTE/DCE products.
- Cable and connector designers ensuring mechanical and electrical mateability between data terminal equipment and modems or line‑terminating equipment.
- Systems integrators and test labs validating compatibility with CCITT/ITU V‑series modem interfaces.
- Legacy system maintainers working with standard V‑series serial data links where a 26‑pin connector is specified.
Related Standards
- CCITT/ITU‑T V.24 (interchange circuit definitions) - functional mapping for signals.
- CCITT/ITU‑T V.10, V.11, V.28 (electrical characteristics for unbalanced/balanced interfaces).
- ISO 2110:1989 (25‑pole DTE/DCE interface) - Annex A covers interoperation with ISO 2110; passive adapters/cables allow one‑for‑one contact mapping.
- Additional V‑series modem recommendations referenced in ISO/IEC 11569 (V.21, V.22, V.23, V.26, V.27, V.32, etc.) for circuit applicability.
Keywords: ISO/IEC 11569, 26‑pole connector, DTE/DCE interface, connector mateability dimensions, contact number assignments, CCITT V.24, V.10, shielded connector, modem interface.