A network technician is troubleshooting severe packet loss and high Near-End Crosstalk (NEXT) error rates on a newly terminated Category 6 unshielded twisted-pair (UTP) cable run. A simple continuity wiremap tester indicates that all eight pins are correctly wired straight-through (pins 1 through 8 match on both ends). However, the link fails certification testing and suffers from extreme signal degradation under load. Which TWO of the following explain the likely cause of this issue or represent the correct troubleshooting steps? (Select TWO.)
- The cable run contains split pairs, where pin continuity is maintained straight-through but wire pairs were matched incorrectly, breaking electromagnetic cancellation.Cevap
- A cable certifier or Time-Domain Reflectometer (TDR) capable of RF frequency analysis must be used to pinpoint NEXT and impedance mismatches along the cable run.Cevap
- CA tone generator and inductive probe should be used to locate the specific pin break along the horizontal cable run.
- DAn optical power meter should be connected to the RJ-45 jack to measure optical attenuation caused by excessive bend radius.
Cevap
The cable run suffers from split pairs (maintaining continuity while disrupting differential pair twisting), and a cable certifier/TDR analyzer must be deployed to locate and measure high-frequency Crosstalk (NEXT) and impedance anomalies.
Split pairs maintain pin-to-pin DC continuity on basic wiremap testers, but separate the intended twisted pairs across different circuits. This disrupts the differential cancellation of electromagnetic interference and causes severe Near-End Crosstalk (NEXT). Detecting split pairs and measuring NEXT requires a cable certifier or advanced Time-Domain Reflectometer (TDR).
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Anahtar Kavram
Identifying split pairs and selecting advanced copper testing tools (cable certifiers/TDR) for crosstalk troubleshooting.