| Full titles | TIA-526-14-D, Optical Power Loss Measurement of Installed Multimode Fiber Cable Plant; IEC 61280-4-1 edition 3.1. TIA-526-7-A, Measurement of Optical Power Loss of Installed Single-Mode Fiber Cable Plant, Adoption of IEC 61280-4-2 edition 2 |
| Publisher | Telecommunications Industry Association (TIA), subcommittee TR-42.11 Optical Systems |
| Current revisions | TIA-526-14-D (13 January 2023). TIA-526-7-A (29 July 2015) |
| Status | Current. 526-14-D replaced 526-14-C (2015) |
| Origin | Both began as Fiber Optic Standard Test Procedures: OFSTP-14 (multimode) and OFSTP-7 (single-mode) |
| Related standards | IEC 61280-4-1, IEC 61280-4-2, IEC 61280-4-5, ANSI/TIA-568.3, ISO/IEC 14763-3 |
What they cover
TIA-526-14 and TIA-526-7 are the North American test procedures for measuring the optical power loss (attenuation) of installed fibre cabling. TIA-526-14 covers multimode fibre. TIA-526-7 covers single-mode fibre and also optical return loss.
Both are now based on the IEC 61280-4 series. The technical content, including the test methods, test cords and uncertainty, is explained on the IEC 61280-4-1 and IEC 61280-4-2 pages in this library. This page covers the TIA documents, their history and where they differ.
Revision history
| Document | Date | Basis |
|---|---|---|
| TIA-526-14 (OFSTP-14) | 1990 | TIA test procedure |
| TIA/EIA-526-14-A (OFSTP-14) | August 1998 | TIA test procedure |
| TIA-526-14 (2010 revision) | October 2010 | IEC 61280-4-1 edition 2 |
| ANSI/TIA-526-14-C | April 2015 | Modification of IEC 61280-4-1 edition 2 |
| TIA-526-14-D | January 2023 | IEC 61280-4-1 edition 3.1 |
| TIA/EIA-526-7 (OFSTP-7) | 1998, reissued 2002 | TIA test procedure |
| TIA-526-7-A | July 2015 | Adoption of IEC 61280-4-2 edition 2 |
IEC 61280-4-2 edition 3 was published in 2024. At the time of writing, TIA-526-7-A still adopts edition 2.
TIA-526-14-C and encircled flux
TIA-526-14-C was an adaptation rather than a straight adoption. It took IEC 61280-4-1 edition 2 and added variances to the encircled flux (EF) launch condition requirements, including where EF is normatively required.
IEC 61280-4-1 applies EF templates at both 850 nm and 1300 nm for both 50 µm and 62.5 µm fibre.
TIA-526-14-D
TIA-526-14-D brings the multimode procedure up to IEC 61280-4-1 edition 3.1, which is edition 3 (2019) consolidated with Amendment 1 (2021). The TIA project to revise 526-14 also set out to add a reference to testing bend-insensitive multimode fibre with an EF-compliant launch cord.
The significant technical changes IEC lists for edition 3 are:
- Annex F on encircled flux revised to harmonise with IEC TR 62614-2, with the EF limits in Tables F.2 to F.5 unchanged
- an equipment cord method added in Annex D
- testing of bend-insensitive multimode fibre included
- measurement uncertainty updated
- additional cabling configurations defined
- Table 5 (spectral requirements) changed
Reference method names
Older TIA documents named the reference methods by letter. Current documents name them by the number of test cords used to set the reference. The letters do not match the IEC annex letters, which causes confusion on older specifications.
| Current name | TIA-526-14-A (multimode) | TIA-526-7 (single-mode) | IEC 61280-4-1 Ed 3 annex | End connections in result |
|---|---|---|---|---|
| One-cord (one-jumper) | Method B | Method A.1 | Annex A | Both |
| Two-cord (two-jumper) | Method A | Not confirmed | Annex C | One |
| Three-cord (three-jumper) | Method C | Not confirmed | Annex B | Neither |
For example, “Method B” on an older multimode specification means the one-cord reference, but Annex B of IEC 61280-4-1 is the three-cord method. Check which document the specification is quoting.
Single-mode: TIA-526-7-A
TIA-526-7-A adopts IEC 61280-4-2 edition 2. It covers attenuation and optical return loss of installed single-mode cabling, including fibre, connectors, adapters, splices and other passive devices. It applies to residential, commercial, industrial, data centre and outside plant cabling, and may be applied to all single-mode fibre types. It is not intended for cabling with active devices such as fibre amplifiers.
Single-mode testing has no encircled flux requirement. EF applies to multimode launch conditions only.
Related TIA and IEC documents
| Document | Relationship |
|---|---|
| IEC 61280-4-1 | Multimode attenuation. Basis of TIA-526-14-D |
| IEC 61280-4-2 | Single-mode attenuation and return loss. Basis of TIA-526-7-A |
| TIA-526-28 | Adoption of IEC 61280-4-5, MPO-terminated cabling tested with MPO test equipment |
| ANSI/TIA-568.3 | Optical fibre cabling and components. Sets the loss limits that test results are compared against |
| ISO/IEC 14763-3 | International testing standard for optical fibre premises cabling |
What it means in practice
- Check which revision a specification calls for. A reference to 526-14-C means the 2015 EF variances; 526-14-D aligns with IEC 61280-4-1 edition 3.1.
- Read old method letters with care. Ask for the reference method by number of cords.
- Check the test report states the reference method, wavelengths and test cords used.
- For multimode, check the source meets encircled flux at the wavelengths the specification requires.
- For MPO-to-MPO links tested with MPO equipment, the applicable procedure is TIA-526-28 or IEC 61280-4-5.
Related reading: Fibre optic loss budget: how to calculate insertion loss · Fibre insertion loss and return loss explained.