Anchor telephone exchange

Ventilation shaft, seen from Canterbury House

Anchor Exchange was an underground, hardened telephone exchange built in Birmingham, England constructed in the 1950s and opened in September 1957. It was located nominally on Newhall St.

It originally formed one of a network of 18 Zone Switching Centres within the United Kingdom (UK) that provided trunk switching facilities within its own charge group and to Group Switching Centres (GSC) within an area broadly comprising the West Midlands and central Wales. The exchange formed part of the trunk mechanisation plan commenced in 1939 to permit operators from originating GSCs to dial through to a distant U.K. subscriber without requiring further operator intervention. Later, it was additionally used to switch subscriber dialled trunk calls after its introduction at Bristol in 1958.

It was subsequently augmented and superseded by a Transit Switching Centre (TSC) equipped with a crossbar switching system (TXK4) which formed part of the Transit Network. It parented two of the first three GSCs at Worcester and Wolverhampton to go-live when the transit network was inaugurated in 1971 which eventually provided universal U.K. automatic subscriber dialling and was completed in 1979.

It was built together with the Guardian Exchange in Manchester and the Kingsway Exchange in London to provide hardened communications in the event of nuclear war. In common with most civil defence structures of the time it was designed to withstand an attack by atomic bombs short of a direct hit.

The exchange took its name from the hallmark of Birmingham Assay Office, which depicts an anchor.