| Full title | Multicore and symmetrical pair/quad cables for digital communications. Part 9: Cables for channels with transmission characteristics up to 2 GHz. Part 10: Cables for cords with transmission characteristics up to 2 GHz. Sectional specifications |
| Publisher | IEC, TC 46/SC 46C (Wires and symmetric cables) |
| Current edition | IEC 61156-9:2016 and IEC 61156-10:2016, both edition 1.0, published 20 April 2016 |
| Status | Published. No later edition listed. Stability date 2029. Published in the UK as BS IEC 61156-9:2016 and BS IEC 61156-10:2016 |
| Related standards | IEC 61156-1 (generic specification); IEC 61156-5 and -6; ISO/IEC 11801-1; ISO/IEC TS 29125 |
What they cover
IEC 61156-9 and IEC 61156-10 are the IEC sectional specifications for balanced cables characterised up to 2 000 MHz. They sit in the IEC 61156 series under the generic specification, IEC 61156-1.
- IEC 61156-9 covers cables mainly for the fixed part of channels as defined in ISO/IEC 11801.
- IEC 61156-10 covers cables mainly for work area cords as defined in ISO/IEC 11801.
Both cover overall screened cables with screened pairs (X/FTP) or unscreened pairs (X/UTP), where X is F, S or SF, and pair-screened cables without an overall screen (U/FTP). Fully unscreened U/UTP construction is not in the scope. Transmission characteristics are specified at 20 °C.
Part 9 states that the cables are intended for channels that use at least four pairs at the same time. It also says the cables are intended to support low voltage remote powering such as IEEE 802.3af, 802.3at and 802.3bt, with guidance in IEC PAS 61156-1-4, IEC TR 61156-1-6 and ISO/IEC TR 29125.
The two categories
| Cable category | For use in | Must also meet (IEC 61156-5) |
|---|---|---|
| Category 8.1 | Class I channels | Category 6A requirements |
| Category 8.2 | Class II channels | Category 7A requirements |
The classes are taken from ISO/IEC TR 11801-9901, which the 2016 text says was planned to be included in the next edition of ISO/IEC 11801-1. Part 9 requires each category to meet all the IEC 61156-5 requirements for the category shown. A note in Part 9 says this makes Category 8.1 backward compatible with Category 6A and Category 8.2 backward compatible with Category 7A.
ISO/IEC 11801-1 limits Class I and Class II channels to 30 m with no more than two connections. See the ISO/IEC 11801-1 page in this library.
Key requirements in Part 9
Installation considerations and materials and construction follow IEC 61156-5. Test methods are those of IEC 61156-1:2007 with Amendment 1:2009, except for the test lengths below.
| Characteristic | Requirement |
|---|---|
| Conductor resistance at 20 °C | ≤ 7.0 Ω per 100 m |
| Resistance unbalance within a pair | ≤ 2.0 % |
| Resistance unbalance between pairs | ≤ 5.0 % |
| Insulation resistance at 20 °C | ≥ 5 GΩ·km (conductor to conductor and conductor to screen) |
| Capacitance unbalance, pair to ground | ≤ 1 200 pF/km at 800 Hz or 1 000 Hz |
| Phase delay, 4 MHz to maximum frequency | ≤ 534 + 36/√f ns per 100 m |
| Delay skew between any two pairs | ≤ 45 ns per 100 m (8.1); ≤ 25 ns per 100 m (8.2) |
| Electrical test length | Not less than 100 m unless stated otherwise |
| Transmission test length | 30 m unless stated otherwise |
Delay and attenuation limits are given per 100 m. For the 30 m test length they are multiplied by 0.3.
Coupling attenuation
Three performance types are recognised, measured by the absorbing clamp method (IEC 62153-4-5) or the triaxial method (IEC 62153-4-9) from 30 MHz to 2 000 MHz.
| Type | 30 to 100 MHz | 100 to 2 000 MHz |
|---|---|---|
| Type I | ≥ 85 dB | ≥ 85 − 20 log10(f/100) dB |
| Type Ib | ≥ 70 dB | ≥ 70 − 20 log10(f/100) dB |
| Type II | ≥ 55 dB | ≥ 55 − 20 log10(f/100) dB |
Part 9 also has tables for attenuation, TCL, ELTCTL, NEXT and PS NEXT, ACR-F and PS ACR-F, PS ANEXT, PS AACR-F and return loss, plus a clause on bundled cables and an introduction to the blank detail specification.
Part 10 for cords
IEC 61156-10 uses the same clause structure and the same set of transmission tables as Part 9, applied to cord cable. Its specific limits, such as conductor resistance and attenuation, were not seen and are not given here.
Place in the IEC 61156 series
| Part | Content | Current edition |
|---|---|---|
| IEC 61156-1 | Generic specification | Ed. 4.0, 2023 |
| IEC 61156-5 | Horizontal floor wiring, up to 1 000 MHz | Ed. 3.0, 2020 |
| IEC 61156-6 | Work area wiring, up to 1 000 MHz | Ed. 4.0, 2020 |
| IEC 61156-9 | Fixed part of channels, up to 2 GHz | Ed. 1.0, 2016 |
| IEC 61156-10 | Cords, up to 2 GHz | Ed. 1.0, 2016 |
The 2016 Part 9 text cites dated editions as normative references: IEC 61156-1:2007 with its 2009 amendment, and IEC 61156-5:2009. Both have since been replaced by newer editions.
In Europe, CENELEC publishes its own cable specification for this frequency range, EN 50288-12-1:2017, for screened cables characterised up to 2 000 MHz for horizontal and building backbone use. See the BS EN 50288 page.
What it means in practice
- A datasheet should state Category 8.1 or 8.2 and the IEC 61156 part, not just Category 8.
- Category 8.1 cable must also meet the Category 6A requirements of IEC 61156-5, and Category 8.2 the Category 7A requirements.
- Check that the cable is a screened construction (U/FTP, F/UTP, F/FTP, S/FTP or similar). U/UTP is outside the scope.
- Transmission results for Part 9 cable are normally based on a 30 m sample, not 100 m.
- Fire performance is set separately, for example a CPR class declared to EN 50575.
Related reading: Cable shielding explained.