CompTIA Network+ (N10-009)Network TroubleshootingEasy
A technician terminates a Cat 6 patch cable and later finds that a workstation connected to it cannot establish a link light, while other cables on the same run work fine. Using a cable tester, the technician sees that pins 1 and 2 show no continuity on one end. Which cabling issue does this indicate?
- AAttenuation
- BCrosstalk
- CSplit pairs
- DOpen circuit
Show answer & explanationAnswer & explanation
Correct answer: D. Open circuit
A lack of continuity between pins on a cable tester indicates a broken or disconnected conductor, known as an open circuit. This differs from split pairs (wires from different pairs improperly combined) or attenuation/crosstalk, which are signal degradation issues rather than a complete break.
Why the other options are wrong
- A. Attenuation is signal loss over distance, not a break in continuity.
- B. Crosstalk is signal interference between pairs, not a continuity fault.
- C. Split pairs would still show continuity, just miswired pairing.
Open Circuit
A break in a cable's conductor that prevents electrical continuity, often caused by poor termination or physical damage.
- Cable testers detect opens by checking continuity per pin
- Common causes: bad crimp, cut wire, corrosion
- Results in no link light or intermittent connection
Memory trick: Open means broken, Short means touching, Split means swapped