|The Exchange working will not be covered by this site and
one should go to numerous other sites for information on such matters.
Main exchanges in the UK started life as manual switchboards, then to electromechanical systems, then crossbar/electronic, followed by System X (electronic) and as this is written in 2021 the UK is converting to IP connectivity.
However, here are some pictures that may be of interest.
Battery room in a 1950's exchange. Note the busbars
feeding the exchange.
Racks of Subscribers meters. These is how the GPO used to bill subscribers.
Last revised: September 10, 2021