What Can I Use If My Wall Jack Is Too Small for an Ethernet Cable?

Check the label and shape of the wall port. An Ethernet jack is wider and normally accepts the same plug as the socket on your computer or router. If the wall jack is the smaller telephone type, replacing the cable with a smaller one won't solve the problem—you'd need the outlet and wiring converted or installed for Ethernet.

Telephone jacks and Ethernet jacks can look similar, but the telephone version is narrower and uses different wiring. You shouldn't force an Ethernet plug into it or expect the existing phone wiring to provide a normal Ethernet connection. Look for a properly wired Ethernet wall jack, or use another networking option such as Wi-Fi, a powerline adapter, or a network cable routed from the router.

A standard Ethernet cable uses an 8P8C plug, commonly called RJ45. The plug size is standardized, so there isn't a smaller Ethernet cable that fits the same way. If it won't fit, the wall outlet probably isn't an Ethernet jack—it may be a smaller RJ11 or RJ12 telephone socket.