Wiring Up Telephone Extensions

To avoid using the really unpleasant Digital Cordless (DECT) phones you can easily obtain telephone extension kits from DIY stores or from Maplin etc. for just a few pounds, and can put the wires near-invisibly on skirting boards and under carpets.

An article that explains how to put in a comprehensive system is as follows:-

Adding additional telephone sockets

You can of course just use a single kit to run an extension up the stairs to a bedroom with little effort.