In article , Stephen
scribeth thus
Hello,

I fitted an extension socket and was reading which colour cable to
connect where. I was using wires with two pairs: blue/white and
orange/white pairs. I read that rarely a third pair (green/white) is
connected to terminals one and six. What were these used for and why
are they no longer used? I am guessing they were used for something
once upon a time otherwise they would not be there.

Thanks,
Stephen.

Http://www.telephonesuk.co.uk/wiring_info.htm

might help...
--
Tony Sayer