The UK Telephone System

This is an over view of how the components of the British telephone system work together (1950's - 1980's).

Click on any part of the picture you have an interest in.

Start in the house with the lady on the telephone making a call. She uses a telephone - connected to internal wiring - connected to a terminal block on the house wall - connected to underground cable.  The house next door is fed by overhead wiring which connects to the underground cable via a terminal block at the top of the pole.  This terminal block called a Distribution Point (DP) as it is at the end of the underground cable.  The underground cable then goes to the exchange, via a pillar and cabinet, where it terminates on the main distribution frame (MDF).

There is a call in progress and a simplified version of a Strowger type automatic exchange can be seen to the top left in schematic below.  The lady in the house is dialling 2369.

Before 1950 there would been fewer automatic exchanges and the line would have been connected to a manual switchboard.  Originally all lines terminated on Switchboards.  The line plant would have also been mostly open copper wires, fed via poles to the customers premises.  Long distance lines (Trunk Routes) would have been on open copper wires as well and many followed the UK road system.  These open wires were of larger diameter than the local open wires and the poles would have been larger, to take the weight.


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Last revised: April 25, 2021