Overview
ISO/IEC 14709-1:1997 - "Information technology - Configuration of Customer Premises Cabling (CPC) for applications - Part 1: Integrated Services Digital Network (ISDN) basic access" - defines design, component and test requirements for ISDN basic access cabling inside customer premises. It is intended for designers, planners, installers and procurers of CPC who need to ensure terminal equipment conforming to ITU‑T Rec. I.430 operates reliably to the Network Termination (NT).
Key topics and technical requirements
- Cabling configurations: point-to-point, short passive bus, extended passive bus, Y‑configuration and star. Each configuration has specific limits on outlets and simultaneous terminals (examples: short passive bus - max 12 outlets / 8 terminals; extended passive bus - max 12 outlets / 4 terminals).
- Electrical and transmission limits:
- Insertion loss (measured at 96 kHz): point‑to‑point ≤ 6 dB; extended passive bus ≤ 4 dB; short passive bus and Y‑configuration indicated as not critical in the table.
- Round‑trip delay: ≤ 2.0 µs for short passive bus and Y; ≤ 0.5 µs differential between first and last outlet for extended passive bus.
- Near‑end crosstalk (NEXT): minimum > 35 dB at 96 kHz; recommended > 54 dB for good immunity.
- Longitudinal conversion loss: ≥ 43 dB at 96 kHz.
- Power feeding: control loop resistance and DC pair unbalance (DC unbalance ≤ 3% if loop resistance > 5 Ω); phantom feeding typically uses two pairs.
- Cabling components and limits: requirements for cables, terminal cords, terminating resistors, outlets, joint boxes and patch cords; recommended maximum spur lengths (outlet spur ≤ 1 m; NT spur ≤ 0.5 m); optional extension cord for point‑to‑point ≤ 25 m.
- Qualification and tests: insertion loss, NEXT, characteristic impedance, ABCD tests such as insulation resistance, DC loop resistance/unbalance, longitudinal conversion loss, impulsive noise, bit error rates (see clause 8).
- Implementation over structured cabling: guidance on using generic cabling per ISO/IEC 11801; note: short passive bus is not supported by generic structured cabling without special adaptation.
Applications and users
- Useful for network engineers, telecommunications installers, facility managers and procurement teams specifying or validating customer premises cabling for ISDN basic access.
- Applies when installing or retrofitting cabling to support ISDN terminal equipment, ensuring interoperability with NT devices and meeting performance tests (e.g., for voice/data over ISDN B‑channels).
Related standards
- ISO/IEC 11801 (Generic cabling for customer premises)
- ISO/IEC 8877 (ISDN interface connector assignments)
- IEC 603‑7 (connectors)
- ITU‑T Rec. I.430 (ISDN user‑network interface Layer 1)
Keywords: ISO/IEC 14709-1:1997, ISDN basic access, customer premises cabling, CPC, insertion loss, NEXT, round‑trip delay, structured cabling, ISO/IEC 11801.