4-pin telephone/network connector used for crimping on to the ends of 2-pair/4-way telephone cable. This is a BT standardised connector used commonly to connect telephones, modems or switches to telephone line sockets that use a 4-way connection.
The 431A 4-way connection is used by single-line connections, most commonly found on older home telephone lines, 4 way connections can also be used for creating an extension. If you wish to connect a multi-line phone system you should use a 6-way line with 631A plugs (also available).
