Patch Cord Test Results
7
bal25.bmp
Low-frequency return loss failure
caused by bad cable
bal26.bmp
High frequency return loss failure
caused by a bad plug
Figure 2. Return Loss Failures at Low and High Frequencies
NEXT Failures
NEXT failures are typically caused by the following:
•
Excessive untwisting of pairs at plug. Most NEXT failures occur at plugs, where the
twist in the wire pairs is interrupted.
•
Poor quality plug
•
Poor quality cable
•
Poorly matched plug and jack (Cat 6/Class E applications)
•
Cable compression (pinches, kinks, etc.)
•
Excessive noise source near cabling under test. Use the impulse noise test to check
for noise.
•
Wrong test limit selected
Fault Information for Long Patch Cords
For 20 m patch cord limits, the tester's automatic diagnostics may help you determine
why a patch cord failed. After an Autotest that failed, press
J
Fault Info to see
information about the failure.
Note
The tester's automatic diagnostics do not usually give complete fault
information for patch cords shorter than 20 m.
