A network technician replaces a damaged modular plug on a Category 6 UTP cable. A basic continuity test shows that all eight conductors line up end-to-end, but the network link suffers from severe Near-End Crosstalk (NEXT) and high packet loss. Which physical cabling mistake is the most likely cause of this issue?
- The conductor pairs were untwisted excessively before being inserted into the RJ-45 connector.Answer
- BA conductor has an open circuit break inside the cable run, preventing signal transmission.
- CThe switch port and host network adapter are operating in a duplex mismatch state.
- DThe cable run exceeds the maximum allowable distance limit for horizontal UTP cabling.
Answer
The conductor pairs were untwisted excessively before being inserted into the RJ-45 connector.
In twisted-pair Ethernet cabling, the tight twisting of conductor pairs provides cancellation against electromagnetic interference and crosstalk. When terminating a Category 6 cable, untwisting the pairs more than 0.5 inches (13 mm) destroys this shielding effect at the connector base, causing signals from one pair to bleed into adjacent pairs (Near-End Crosstalk). A basic continuity tester will still show a pass because electrical connectivity is maintained.
Step-by-Step Solution
Key Concept
Excessive untwisting of copper conductor pairs during RJ-45 connector termination causes Near-End Crosstalk (NEXT).