| Full title | Multicore and symmetrical pair/quad cables for digital communications, Parts 11 to 14 (symmetrical single pair cables). Connectors for electrical and electronic equipment: shielded or unshielded free and fixed connectors for balanced single-pair data transmission with current-carrying capacity (IEC 63171 series) |
| Publisher | IEC. Cables: TC 46/SC 46C. Connectors: TC 48/SC 48B |
| Current edition | IEC 61156-11:2023 + AMD1:2025; IEC 61156-12:2025; IEC 61156-13:2023; IEC 61156-14:2025; IEC 63171:2025 (general specification) |
| Status | Published. See the tables below for each part |
| Related standards | ISO/IEC 11801-1 with Amd 1:2025; IEEE 802.3cg; IEC 61156-1, -5, -6 |
What they cover
Single pair Ethernet uses one balanced twisted pair for data, and can carry power on the same pair. IEC specifies the components in two series. IEC 61156-11 to -14 are sectional specifications for single pair cables. The IEC 63171 series specifies single pair connectors.
All four of these cable parts allow unscreened or screened cable, depending on the MICE environment and installation conditions. Each includes a blank detail specification in Annex A. Each says the cables are intended to support low voltage remote powering, but not connection to low impedance sources such as the public mains.
Single pair cables: IEC 61156-11 to -14
| Part | Use | Frequency | Cable types | Current edition |
|---|---|---|---|---|
| IEC 61156-11 | Horizontal floor wiring | Up to 1.25 GHz | T1-B to 600 MHz; T1-C to 1.25 GHz | Ed. 2.0, 2023; Amendment 1, 2025 |
| IEC 61156-12 | Work area wiring | Up to 1.25 GHz | T1-B 0.1 to 600 MHz; T1-C 0.1 MHz to 1.25 GHz | Ed. 2.0, April 2025 |
| IEC 61156-13 | Horizontal floor wiring | Up to 20 MHz | A-1000 (1 km channels); A-400 (400 m channels) | Ed. 1.0, May 2023 |
| IEC 61156-14 | Work area wiring | Up to 20 MHz | A-1000W; A-400W | Ed. 1.0, May 2025 |
Parts 11 and 12 are for single balanced pair applications in office, home and industrial cabling to ISO/IEC 11801-1. They give 1000BASE-T1 as an example application. Parts 13 and 14 are for 10 Mb/s over a single twisted pair in channels up to 1 km.
In IEC 61156-14, the A-1000W type has no attenuation de-rating compared with A-1000 in Part 13. The A-400W type includes attenuation de-rating compared with A-400.
Change of type names
The 2023 edition of Part 11 named its two types T1-C (600 MHz) and T1-D (1.25 GHz). Amendment 1:2025 renamed them T1-B and T1-C, matching Part 12:2025. Check which edition a datasheet refers to before comparing type letters.
Key requirements in IEC 61156-11
| Requirement | IEC 61156-11:2023 |
|---|---|
| Conductor | Solid annealed copper |
| Nominal conductor diameter | 0.4 mm to 0.65 mm; up to 1.05 mm may be used |
| Maximum conductor resistance at 20 °C | 72.5 Ω/km |
| Resistance unbalance within a pair | ≤ 2.0 % |
| Installed bend radius | Cable must accept 4 × outside diameter unless otherwise specified |
| Operating temperature, static | At least −20 °C to +60 °C |
| Transmission test length | 100 m; 50 m may be used for the 1.25 GHz type |
With remote powering, the conductor temperature must not exceed the 60 °C maximum static operating temperature. Where several pairs are in one cable for parallel systems, the bundled cable clause applies and pair-to-pair resistance unbalance must not exceed 5.0 %.
Edition 2 of Parts 11 and 12 added the 1.25 GHz cable type and introduced low frequency coupling attenuation to describe screening below 30 MHz.
Single pair connectors: IEC 63171
IEC 63171 is the general specification. It sets common mechanical, electrical, transmission and environmental requirements and test schedules, but does not describe a mating interface. Each detail specification defines one connector type, and the type number equals the part number.
| Part | Connector | Data frequency | Edition seen |
|---|---|---|---|
| IEC 63171 | General requirements and tests | Common to series | Ed. 2.0, April 2025 |
| IEC 63171-1 | Type 1, 2-way, copper LC style, shielded or unshielded | Up to 600 MHz | Ed. 2.0, April 2024 |
| IEC 63171-2 | Type 2, 2-way, shielded or unshielded | Up to 600 MHz | Ed. 1.0, May 2021 |
| IEC 63171-4 | Type 4, multimedia connector, up to 8 ways | Up to and above 3 000 MHz shielded; up to 600 MHz unshielded | Ed. 1.0, 2022, with Corrigendum 1:2023 |
| IEC 63171-5 | Type 5, 2-way M8 and M12 circular, shielded or unshielded | Up to 600 MHz | Ed. 1.0, September 2022; Corrigendum 1:2024 |
| IEC 63171-6 | 2-way and 4-way (data/power), shielded | Up to 600 MHz | Ed. 2.0, October 2021 |
| IEC 63171-7 | Shielded circular, 4 to 7 ways, size 12 (M12, P12 or C12 locking) | Up to 600 MHz on the data pair | Ed. 1.0, May 2023 |
IEC 63171-1 gives a current-carrying capacity of up to 2.0 A at 60 °C. The second edition of IEC 63171-6 added a 2 250 V DC voltage proof requirement, a mechanical shock requirement and two M8 styles. IEC 63171-7 uses codings, called Type I, Type II and so on, to stop incompatible connectors mating.
For a given type, shielded and unshielded versions are interoperable for transmission performance. The shielded version has better alien crosstalk and coupling attenuation. The 2025 general specification added requirements for multipole and combined connectors and aligned transmission requirements with ISO/IEC 11801-1.
How they relate to other standards
- ISO/IEC 11801-1 Amendment 1:2025 adds single pair component categories and channel classes T1-A, T1-B and T1-C. See the ISO/IEC 11801-1 page.
- IEEE 802.3cg defines 10 Mb/s single pair Ethernet. See the IEEE 802.3cg page.
- IEC 61156-11 refers to IEC 61156-5 for materials and construction. IEC 61156-12 and -14 cite IEC 61156-6 as a normative reference.
What it means in practice
- A single pair cable datasheet should state the IEC 61156 part and the cable type, such as T1-B or A-1000, and the edition.
- Use Parts 11 and 13 for fixed horizontal cable and Parts 12 and 14 for cords.
- Connector types from different IEC 63171 parts have different mating interfaces. Confirm the type number at both ends of a link.
- IEC 63171-6 is the 2-way and 4-way shielded connector part. IEC 63171-1 is the LC style type.
Related reading: M12 connectors and industrial connectivity · Industrial RJ45 vs M12.