The TIA-568-3.D also recommends using of reference-grade patch cables to “reduce uncertainty and improve the reproducibility of measurements.”

As such, the 3.D now defines test cord allowances based on the quality of connections where the testers plug in.

Thus, SOURCE TEST CABLE and METER TEST CABLE define the type of connection where the testers plug in. So if you are using off-the-shelf patch cables, select STANDARD, while if you are using high-quality reference-grade patch cables, select REFERENCE.

Some key notes:

1) Reference-grade cables are a recommendation, not a requirement.

2) SOURCE TEST CABLE and METER TEST CABLE can be different.

3) For multimode testing: encircled flux mode controller cables are always considered reference-grade.

4) These test cable settings count against the total number of connections in the link under test. Understanding this will become important as we proceed to the next step in the procedure.