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Old 27th Aug 2022, 5:56 pm   #7
OscarFoxtrot
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Join Date: Apr 2011
Location: Edinburgh, UK.
Posts: 805
Default Re: Practical Electronics mag - Telephone exchange project

AFAICS from the brief description, switching with multiple extensions.

The two telephones with relay logic was described here

https://www.vintage-radio.net/forum/...8&postcount=20

Cook Abbott - Electronics and Wireless World.
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