CompTIA A+ Core 1 (220-1201)Hardware and Network TroubleshootingHard
A network technician uses a cable certifier on a newly installed Cat6 patch cable and finds that pins 3 and 6 show a split-pair wiring fault, even though the cable passes a basic continuity test. Which network symptom is MOST likely to result from this specific fault?
- AThe cable will work perfectly since continuity was confirmed
- BThe switch port will be automatically disabled by STP
- CComplete loss of link light with no connectivity at all
- DIntermittent slow speeds and increased crosstalk-related errors
Show answer & explanationAnswer & explanation
Correct answer: D. Intermittent slow speeds and increased crosstalk-related errors
A split pair occurs when wires from two different twisted pairs are used together instead of their intended pair partner, defeating the twist's noise cancellation. This passes basic continuity testing (since each pin connects end to end) but introduces crosstalk between pairs, resulting in intermittent errors and degraded throughput rather than a complete link failure.
Why the other options are wrong
- A. Continuity testing alone does not detect wiring pair integrity issues like split pairs; a wire map/certifier test does.
- B. STP does not detect or respond to physical layer wiring faults like split pairs.
- C. A split pair typically still establishes link since continuity per pin exists; it degrades quality rather than blocking the connection entirely.
Split Pair Cable Fault
A wiring error where two wires from different twisted pairs are used as if they were a matched pair, passing continuity tests but causing crosstalk and performance issues.
- Passes basic continuity, fails wire-map/certifier test
- Twisted pairs cancel noise; splitting pairs defeats this
- Causes crosstalk, intermittent errors, reduced speed
Memory trick: Twisted pairs dance together — split them up and they start stepping on each other's toes (crosstalk).