I bought an HDMI KVM extender to connect a computer on the second floor to a TV on the ground floor. The transmitter and receiver work perfectly when placed close together and connected with a single Ethernet cable, but the connection fails when each unit is plugged into an Ethernet wall socket on a different floor. The extender's instructions say it supports up to 120 meters over Category 5 or better cable, so the distance should not be a problem. I'm unsure whether the wall sockets are connected to each other, whether the installed cable is suitable, or whether there is another wiring issue. What should I check, and how should these wall connections be linked?
4 Answers
First, locate where the Ethernet cables from both wall sockets meet. They may end at a patch panel, where you can connect the two corresponding ports with a short Ethernet cable, or they may have loose RJ-45 plugs that can be joined with an Ethernet coupler. The sockets won’t communicate unless their cable ends are actually connected.
If the cables end in a patch panel, connect the two matching ports directly rather than plugging them into a network switch. If the wiring is unfinished or the four pairs are simply loose, terminate them using the same standard on both ends—normally T568A or T568B—and verify the result with a cable tester. Also make sure the installed cable is at least Category 5e and that no intermediate couplers or damaged segments are present.
You can troubleshoot the wall wiring with a laptop, network switch, or any device that has Ethernet link lights. Plug one into each jack and check whether the ports show a link. You can also remove the wall plates to see where the cables run and look for a utility closet, attic, crawlspace, or cabinet containing the other ends. A basic cable tester can confirm whether all pairs are connected correctly.
This extender probably isn’t using Ethernet networking or TCP/IP. It’s using the Ethernet-style cable as a direct point-to-point connection for HDMI and USB signals. That means it generally cannot pass through a router, network switch, or other active networking equipment. The transmitter and receiver need a continuous, correctly wired cable path between them.
Exactly—calling it an Ethernet extender can be misleading. Category-rated twisted-pair cable is recommended, but the devices are not necessarily sending normal network packets.