Telephone extension cabling confusion?

not in the uk with that colour code then? hard to tell but if you are wanting to wire an extention, then all you need to do is choose 3 colours and make them the same to terminals 2, 3 and 5 in the main socket, and at the extention socket, 2 and 5 is the volts coming from the exchange and 3 is the bell wire (to make the extention socket ring). if you have broadband/adsl, the filter makes an extention phone ring so you only need a pair of wirws to 2 and 5. i would use blue and white for your extention. if bell wire needed to 3 use red. hope this helps. 1 4 2 5 3 6 this is how they normally appear in a jack/socket.