Can I Plug An Ethernet Cable Into The Wall Outlet. Yes, if the connection is an rj45 connector for all other types you also need a modem, but even with a modem that will be a rather stupid idea. If your wall output is really ethernet which is possible if your wall is a fibre media convertor or ethernet wired apartment (and not dsl for example) then it is technically possible to plug a pc into it directly, but, if you need to ask the question, doing so is probably a bad idea because
Where you have a mains cable which has a plug or connector at each end, such one for a monitor, i'd say it as plug it.
That's fast enough to transfer large files or to stream video quickly to your 4k hdtv. One powerline adapter was also plugged into a nearby outlet, with its ethernet cable connected to a port on the router. If you don't have one, you need to get one. From the cable modem ethernet port i plugged into the untrusted port on my router/firewall.