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Old 23rd Mar 2021, 9:50 pm   #3
JohnBHanson
Heptode
 
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.
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