| Full title | Specification for the testing of balanced and coaxial information technology cabling. Part 1: Installed balanced cabling as specified in ISO/IEC 11801-1 and related standards |
| Publisher | IEC, technical committee TC 46 |
| Current edition | Edition 5.0, 2019-09. Replaces Edition 4.0 (2015) |
| Status | Current. IEC stability date 2028 |
| Related standards | ISO/IEC 11801-1, IEC 61935-1-1, IEC 61935-1-2, IEC 61935-2, IEC 61935-3, ANSI/TIA-1152-A, EN 61935-1 |
What it covers
IEC 61935-1 sets out how installed balanced cabling is measured and how accurate a field tester must be. It covers the cabling parameters identified in ISO/IEC 11801-1.
It applies to cabling built from cables to IEC 61156 and connecting hardware to IEC 60603-7, or to IEC 61076-3-104, IEC 61076-3-110, IEC 61076-2-101 and IEC 61076-2-109. Other cables or connectors may need extra tests.
The document is written for 100 Ω, 4-pair cabling. The same principles apply to 120 Ω or 150 Ω cabling with a matching measurement system. Two-pair links that share a sheath with other links are tested as 4-pair cabling.
How the document is organised
- Clause 4: reference laboratory measurement procedures, using a network analyser.
- Clause 5: field test measurements, test configurations and reporting.
- Clause 6: field tester accuracy requirements and how to verify them.
The standard separates three kinds of tester. Certification testers measure to this document with accuracy traceable to national standards. Qualification testers (IEC 61935-3) check whether cabling supports a given network application. Verification testers check connectivity only.
Field test parameters
Clause 5 lists the parameters a field tester measures on installed cabling.
| Parameter | What it shows |
|---|---|
| Wire map (connectivity) | Correct pin-to-pin termination and pairing |
| Length | Physical length derived from propagation delay |
| Propagation delay and delay skew | Signal travel time, and the difference between pairs |
| Insertion loss | Signal loss along each pair |
| NEXT and PS NEXT | Crosstalk measured at the near end |
| ACR-N and PS ACR-N | Near-end crosstalk relative to insertion loss |
| ACR-F and PS ACR-F | Far-end crosstalk relative to insertion loss |
| Return loss | Signal reflected back by impedance mismatches |
| DC loop resistance | Resistance of each pair |
| DC resistance unbalance between pairs | Resistance difference between pairs |
| Alien crosstalk (PS ANEXT, PS AACR-F) | Crosstalk coupled in from neighbouring cables |
Two optional measurements sit in separate parts. IEC 61935-1-1 covers transverse conversion loss (TCL) and equal level transverse conversion transfer loss (ELTCTL). IEC 61935-1-2 covers resistance unbalance within a pair.
Test configurations
The standard defines reference planes for three configurations: the permanent link, the CP link (a permanent link that includes a consolidation point) and the channel.
- Permanent link tests use test equipment adapter cords. The adapter cord’s contribution is excluded from the result.
- Channel tests include the user’s own patch and equipment cords, which stay part of the measured channel.
Field tester accuracy levels
Clause 6 defines accuracy levels. Each has its own worst-case accuracy tables for insertion loss, NEXT, ACR-N, ACR-F and return loss. Edition 5 added Level VI to 2 000 MHz. The class each level is normally used for is shown below, based on test equipment manufacturers’ documentation.
| Level | Typical use | Frequency |
|---|---|---|
| IIe | Class D (Category 5e) | 1 to 100 MHz |
| III | Class E (Category 6) | 1 to 250 MHz |
| IIIe | Class EA (Category 6A) | 1 to 500 MHz |
| IV | Class F | 1 to 600 MHz |
| V | Class FA | 1 to 1 000 MHz |
| VI | Class I and Class II | 1 to 2 000 MHz |
Clause 6 also defines how tester performance is checked: output signal balance, common mode rejection, residual NEXT and FEXT, dynamic accuracy, directivity, source match and tracking.
Related standards
| Standard | Relationship |
|---|---|
| ISO/IEC 11801-1 | Sets the cabling classes and limits that IEC 61935-1 measures against |
| IEC 61935-2 | Test methods for patch cords and work area cords |
| IEC 61935-3 | Testing of installed home cabling (ISO/IEC 15018), including qualification testing |
| ANSI/TIA-1152-A (2016) | North American field tester standard. Shares Levels IIe, III and IIIe, and adds Level 2G for Category 8 |
| EN 61935-1:2009 | Current European version. Based on IEC 61935-1:2009 (modified) and referencing EN 50173. It has not been updated to Edition 5 |
| EN 50346 | Former CENELEC standard for testing installed cabling. Now withdrawn |
What it means in practice
- Check the tester’s stated accuracy level matches the class being certified. Class EA links are normally certified with a Level IIIe tester or higher.
- Check the test report states permanent link or channel. The limits are different.
- Check the tester calibration date and the adapter cords used.
- Results close to the limit fall within the tester’s accuracy band. Annex A of the standard gives guidance on reporting marginal results.
Related reading: How to read a cable test certificate.