DTX-PCxxS Patch Cord Test Adapters
Users Manual
6
Why Patch Cords Fail
Patch cords may fail because of faulty wiring, poor workmanship, poor quality
materials, or damage to the cable or plug.
Failures may also occur when the patch cord adapter jacks need replacing or a patch
cord adapter is defective. If the adapters' performance was characterized when the
adapters were new, use the results and the reference patch cord to check the adapters'
performance. See Appendix A.
The following sections give typical causes for wire map, return loss, and NEXT failures.
Wire Map Failures
Wire map failures are typically caused by the following:
•
Wires connected to wrong pins at plug
•
Faulty connections
•
Damaged plug
•
Damaged cable
•
Wrong Outlet Configuration selected in setup
•
Mix of T568A and T568B wiring standards (1,2 and 3,6 crossed)
•
Conductive material stuck between pins at plug
Return Loss Failures
Return loss failures are typically caused by the following:
•
Cable impedance not 100
Ω
•
Patch cord handling causing changes in impedance
•
Excessive untwisting of pairs at plug
•
Poor quality plug
•
Cable impedance not uniform (poor quality cable)
•
Cable compression (pinches, kinks, etc.)
•
Poorly matched plug and jack (most often affects Cat 6/Class E applications)
•
Wrong test limit selected
The return loss plot can often tell you if a patch cord failed because of bad cable or a
bad plug:
•
Return loss failures at low frequencies (below 50 MHz) tend to be caused by the cable.
•
Return loss failures at high frequencies tend to be caused by plugs.
