I remove the faceplate, and the wiring inside looked a bit strange.
In the house there is one master socket where the phone cable from the outside is connected with 3 further extensions hard wired to it. All the sockets around the house work fine. Photo of master socket is here:
Two of the extensions are wired on both ends as per usual - i.e. pins and wire colours, but the third one - the one I was looking at today is wired as follows:
At the master socket end: Pin2: White with Blue Pin5: Blue with White All other wires are cut.
On the extension socket end the wiring is as per this photo: http://tinypic.com/r/2z5j2tv/5
Note that this is also the socket used for ADSL and phone.
Is this right (I assume it is, as it works...)?
If I want to use a different face plate, will I have to connect all 4 cables as per the usual way?