From the course: CompTIA A+ Core 1 (220-1201) Cert Prep

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Structured cabling

Structured cabling

From the course: CompTIA A+ Core 1 (220-1201) Cert Prep

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Structured cabling

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- Let's talk about testing your network connections. With all the different cables, connectors, and ports we use, sometimes you need a quick, simple way to make sure they're actually working. One of the easiest ways to do this is with a loopback plug, or loopback cable. So what is it? A loopback plug is a small device that takes the output signal from a port, and loops it right back into the input of the same port. You just plug it into the port that you want to test. If the port can send and receive the signal correctly, you know it's functioning properly. Here's an example. For RJ 45 ethernet ports, loopback plugs are wired so that the transmit and receive lines are crossed. That means the signal goes out, and immediately returns through the same connector. You'll often see wiring diagrams showing exactly how this works for 10 or 100 megabit ethernet, as well as gigabit and fast ethernet standards. And yes, technicians often have small loopback plugs they carry around with them…

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