UK Telephone Wiring When the front screws are removed the complete lower portion of the socket including the IDC connectors for user wiring can be pulled out. They connect to the back plate by means of a fixed plug. The fixed plug is a standard BT plug and socket and allows all the internal wiring TELEPHONE SOCKET WIRING - HOW TO DO IT Incorrect wiring may cause faulty operation or damage to the system. Terminating the wires No wire stripping or soldering is necessary to make a good termination. The Krone tool (IDC - Insulation Displacement Connector) or cheap plastic wiring tool will be used to connect the wires to the socket. Telephone Wiring Colour Code - BT Telephone Extension Telephone Wiring Colour Code BT NTE5 Master Socket. The following pictures show the standard BT Telephone Wiring Colour Code used with the BT NTE5 Master Socket. Please note you must use the correct inserter tool to push the wires in to the phone socket IDC connectors. Failing to do so will open the blades permanently damaging the connector. Wiring Information - Telephones UK The wiring diagram for a master LJU socket is shown here. Note that the pictorial view shown above only serves to indicate the two differing types of sockets and wiring connections. Contrary to how it might seem, C1 is connected to terminals 2 & 3, not 1 & 4.