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Old 23rd Mar 2021, 9:50 pm   #3
Join Date: Aug 2009
Location: Worthing, Sussex, UK.
Posts: 593
Default Re: GEC Loudspeaking telephone

Looking at the circuit diagrams of the LST2a and LST2b tells an interesting
story - the optimisation of the line circuit for single line working including
the change from using relays to using contacts on the ans switch.

Very interesting.
JohnBHanson is offline   Reply With Quote