If a technician suspects a crossed pair in a twisted-pair Ethernet cable, which instrument should be used to confirm?

If a technician suspects a crossed pair in a twisted-pair Ethernet cable, which instrument should be used to confirm?

• A. Multimeter
• B. Toner and probe
• C. OTDR
• D. Cable continuity tester

Answer: (D)

Testing for a crossed pair means you need a tool that can confirm exactly which conductor from one end connects to which pin on the other end. A cable continuity tester does this by sending signals through each wire and showing a pin-to-pin map. With that map, you can see if the two wires that form a twisted pair ended up on the wrong pins, which is what a crossed pair is. This makes it the most direct and reliable way to confirm the issue on a twisted-pair Ethernet cable. A multimeter can check continuity, but it isn’t practical for mapping all eight conductors at once and doesn’t provide a clear end-to-end pinout. Toner and probe helps locate a cable in a wall or bundle, not verify the precise pin connections. An OTDR is designed for fiber optics, not copper Ethernet. So the cable continuity tester is the right choice for confirming a crossed pair.

Testing for a crossed pair means you need a tool that can confirm exactly which conductor from one end connects to which pin on the other end. A cable continuity tester does this by sending signals through each wire and showing a pin-to-pin map. With that map, you can see if the two wires that form a twisted pair ended up on the wrong pins, which is what a crossed pair is. This makes it the most direct and reliable way to confirm the issue on a twisted-pair Ethernet cable.

A multimeter can check continuity, but it isn’t practical for mapping all eight conductors at once and doesn’t provide a clear end-to-end pinout. Toner and probe helps locate a cable in a wall or bundle, not verify the precise pin connections. An OTDR is designed for fiber optics, not copper Ethernet. So the cable continuity tester is the right choice for confirming a crossed pair.