Overview
ISO/IEC 14709-2:1998 specifies requirements for Customer Premises Cabling (CPC) used to connect equipment to ISDN primary rate (1,544 Mbit/s and 2,048 Mbit/s) interfaces. Intended for designers, planners, procurement teams, installers and testers, the standard defines design rules, component criteria, measurement points and acceptance levels for dedicated ISDN primary access cabling and guidance for implementing ISDN over generic cabling (ISO/IEC 11801).
Key Topics and Requirements
- Scope: Design and configuration of CPC for ISDN primary access and leased lines for both 1.544 Mb/s and 2.048 Mb/s interfaces.
- Insertion loss: Measured from NT1 to TE (or NT1 to NT2) - at 0.772 MHz with 100 Ω source/load for 1.544 Mb/s and at 1.024 MHz with 120 Ω for 2.048 Mb/s. Maximum insertion loss shall not exceed 6 dB (per ITU‑T I.431).
- Near‑end crosstalk (NEXT):
- Link requirement: > 25 dB up to 1.0 MHz (aligns with ISO/IEC 11801 Class B and ITU‑T I.431).
- For 100 m cable: > 43 dB up to 0.772 MHz and > 41 dB up to 1.0 MHz.
- Cables and topology: Use balanced twisted pair or star quad cable (screened or unscreened). Two pairs must be available (one transmit, one receive); polarity should be maintained.
- Insulation resistance: > 50 MΩ·km measured at 20 °C and 500 V dc; 50 V dc tests may indicate existing defects.
- Spurs: Spurs (bridged taps) are not permitted in ISDN primary access cabling.
- Power feeding: If power is provided over cabling, a separate dedicated pair is required.
- Electromagnetic compatibility (EMC): Minimize interference (motors, adjacent circuits) by screening, balance and good installation practice; emission and immunity standards (CISPR 22, CISPR 24) apply.
- Connectors and cords: Sockets should follow ITU‑T I.431 recommendations or use hardwiring; cords must meet the same balanced cable requirements.
Applications and Users
- Network and telecom engineers implementing ISDN primary access within enterprise or campus premises
- Cabling designers, contractors and installers planning point‑to‑point ISDN links
- Facilities and building managers procuring cabling and acceptance testing services
- Test and commissioning teams verifying insertion loss, NEXT, insulation resistance and cabling integrity
Related Standards
Keywords: ISO/IEC 14709-2, ISDN primary rate, customer premises cabling, CPC, insertion loss, NEXT, generic cabling, ISO/IEC 11801, EMC.