There is some confusion about the requirement for the bell wire in a UK telephone installation, and a number of myths have arisen - especially around DSL filtering. This page aims to explain why the bell wire exists, and why you might still need it.

History

When the 'new' BT Phone Socket was introduced in the early 1980s the telephone system had not yet been deregulated - British Telecom had a virtual monopoly, subscribers rented phones from them, and pulse dialling (aka Loop Disconnect) was the order of the day. The BT Phone Socket was a step forward, to allow subscribers to buy their own phones and simply plug them in. Before the BT Phone Socket, an engineer would have to install a new phone because the wiring was more complicated.