Overview
IEC 61156-9:2016 is an international sectional specification in the IEC 61156 series for multicore and symmetrical pair/quad cables for digital communications. It specifies cables intended primarily for the fixed part of channels defined by ISO/IEC 11801 and ISO/IEC TR 11801-9901, with transmission characteristics measured up to 2 000 MHz (2 GHz) at 20 °C. The standard covers overall-screened and pair-screened constructions - X/FTP, X/UTP (X = F, S or SF) and U/FTP - and recognises two cable categories: Category 8.1 (for Class I) and Category 8.2 (for Class II).
Key Topics and Requirements
This sectional specification addresses both construction and performance aspects, including:
- Materials & cable construction: overall screens, pair screening and sheath requirements for high-frequency channels.
- Electrical characteristics & tests: conductor resistance, resistance unbalance, dielectric strength, insulation resistance, mutual capacitance and capacitance unbalance, transfer impedance, coupling attenuation, and current-carrying capacity.
- Transmission characteristics: velocity of propagation, phase and differential delay (delay skew), attenuation up to 2 GHz, unbalance attenuation (TCL), near‑end crosstalk (NEXT), far‑end crosstalk (ACR‑F), alien (exogenous) NEXT/ACR (ANEXT/AFEXT), impedance, and return loss.
- Mechanical requirements: dimensional tolerances, tensile strength and elongation of conductors/insulation/sheath, crush and impact tests, bending and repeated bending performance.
- Environmental ageing and safety: thermal ageing, cold/heat shock, damp heat, UV resistance, solvent exposure, salt mist, water immersion, wicking, flame propagation, smoke and halogen gas evolution, and integrated fire testing.
- Bundled cable behaviour: crosstalk and heat considerations for cables installed in bundles.
The document includes referenced test methods and tabulated performance criteria for coupling attenuation, NEXT/PS NEXT, ACR‑F, TCL/ELTCTL, and return loss.
Applications and Who Uses This Standard
IEC 61156-9 targets professionals and organizations involved in high-performance structured cabling and digital communications, including:
- Cable manufacturers and R&D teams developing Category 8‑class products
- Data center and enterprise network designers specifying fixed-channel cabling
- Installation and commissioning contractors verifying compliance
- Test labs and certification bodies performing electrical/mechanical testing
- Standards writers and procurement teams specifying Class I/Class II channel infrastructures
Practical uses include fixed cabling for high-frequency enterprise and data‑center channels that require four-pair simultaneous operation and support for remote powering (e.g., Power over Ethernet: IEEE 802.3af/at/bt).
Related Standards
- ISO/IEC 11801 and ISO/IEC TR 11801-9901 (channel classes and cabling topology)
- Other parts of IEC 61156 series (multicore and symmetric cables)
- IEC PAS 61156-1-4, IEC TR 61156-1-6 (installation and power delivery guidance)
- IEEE 802.3af/at/bt (PoE specifications)
Keywords: IEC 61156-9, Category 8.1, Category 8.2, X/FTP, X/UTP, U/FTP, 2 GHz cabling, ISO/IEC 11801, structured cabling, PoE, high-frequency channels.
Open preview (PDF)Multicore and symmetrical pair/quad cables for digital communications - Part 9: Cables for channels with transmission characteristics up to 2 GHz - Sectional specification
