Adam Funk wrote:
There's a phone socket on the wall just outside the "networking
cupboard" at home (well, built-in wardrobe with the router & modem on
a shelf). I'd like to change it to a double --- phone beside RJ45 on
one faceplate & connect the RJ45 to the router inside. Instead of
wiring a socket on the wall to a socket inside the cupboard, then
connecting a patch cable to the router, is there any reason not to
just put an RJ45 plug on one end of a piece of cable & the RJ45 socket
on the other end?

Others will answer on the practical aspects of doing what you ask, but
I'd stick with the two-socket approach, unless there was a really
pressing reason not to have a second socket.

--
Mike Barnes
Cheshire, England