Overview
ISO/IEC TR 9578:1990 is a technical report that compiles and describes the physical-layer medium interface connectors used in local area networks (LANs). It documents the interface devices used between terminal equipment and the trunk coupling unit for trunk cables, focusing on connector types for three transmission media: copper wire / twisted pair, coaxial, and fibre optic. Cables or wires themselves are explicitly excluded from the scope. This report is informational (Technical Report type 3) and serves as a compendium to reduce confusion about connector usage across ISO/IEC LAN standards.
Key topics and technical requirements
- Connector groups covered:
- Copper / twisted pair: D‑subminiature connectors, medium interface connectors (MIC), modular jacks/plugs.
- Coaxial: BNC, N‑type, F‑type, TNC, Twinax and related RF connectors.
- Fibre optic: F‑SMA type and duplex fibre connectors.
- Representative performance and feature notes (as given in the report):
- D‑subminiature connectors: working voltage ~25 V DC/AC peak; insulation resistance ≥ 5 GΩ; contact resistance ≤ 10 mΩ.
- Medium Interface Connector (MIC): hermaphroditic design (two identical units mate), self‑shorting feature, working voltage 30 V AC at 1 A max, insulation resistance ≥ 1000 MΩ, contact resistance unmated ~40 mΩ avg / mated ~20 mΩ avg, screen ~25 mΩ avg.
- Shield continuity for CSMA/CD (Ethernet): multiple contact points around male shell to maintain shield continuity ≤ 5 mΩ.
- Mechanical details: mating-face drawings, contact arrangements, and locking/docking mechanisms are provided for information. The report references IEC detail specifications for dimensional and contact requirements rather than redefining them.
Applications and users
- Who uses this report
- LAN hardware designers and equipment manufacturers selecting physical connectors for network interfaces.
- Network integrators and installers verifying connector compatibility for trunk and terminal connections.
- Test laboratories and compliance engineers assessing physical-layer connections.
- Procurement and standards committees seeking consistent references across ISO/IEC LAN specifications.
- Practical uses
- Choosing a connector family (D‑sub, MIC, BNC, FSMA, etc.) compatible with an intended LAN technology (Ethernet, Token Ring, FDDI).
- Ensuring mechanical/electrical mating, shielding and grounding practices meet referenced performance limits.
- Cross-referencing connector types used across multiple ISO/IEC LAN standards to avoid interoperability issues.
Related standards
- ISO 8802‑3 (Ethernet / CSMA/CD), ISO 8802‑5 (Token Ring), ISO 9314 (FDDI)
- IEC connector standards: IEC 807‑2 / 807‑3 (D‑sub detail specs), IEC 169 series (BNC, N, TNC, F), IEC 874‑2 (F‑SMA fibre connector)
- CCITT/ITU recommendations for layer‑1 interfaces
This compilation helps stakeholders align connector selection and physical‑layer implementation with internationally recognized LAN interface practices.