CompTIA Network+ (N10-009)Network TroubleshootingHard
A technician uses a certified cable tester to test a Cat 6 run and finds that Near-End Crosstalk (NEXT) values exceed the acceptable limit at one end of the cable. What does this measurement indicate?
- AThe cable is experiencing excessive attenuation due to distance
- BThe cable exceeds the maximum supported length for the standard
- CThere is a break in continuity somewhere along the cable run
- DSignal is leaking between wire pairs near the termination point
Show answer & explanationAnswer & explanation
Correct answer: D. Signal is leaking between wire pairs near the termination point
NEXT measures the amount of signal coupling from one pair to another near the point where the cable is terminated. High NEXT indicates poor termination quality—such as excessive untwisting of pairs at the connector—allowing crosstalk between pairs, which degrades signal integrity.
Why the other options are wrong
- A. Attenuation is a separate measurement reflecting signal loss over distance, unrelated to crosstalk between pairs.
- B. Length issues are measured separately and reported as a distance value, not as a NEXT reading.
- C. A continuity break would show as an open circuit fault, not a crosstalk measurement.
Near-End Crosstalk (NEXT)
A measurement of signal interference between wire pairs within the same cable, measured at the end closest to the signal source, often caused by poor termination.
- High NEXT often results from excessive untwisting of pairs at the connector
- Measured in dB; higher dB loss values indicate less crosstalk (better performance)
- Certified cable testers report NEXT as pass/fail against category standards
Memory trick: NEXT = Noise EXchanged between Twisted pairs near the plug.