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Old 22nd Aug 2019, 11:05 pm   #2
Oldcodger
Octode
 
Join Date: Oct 2014
Location: West Midlands, UK.
Posts: 1,927
Default Re: Boost the ringer current instead of ...

dag- BT had two alternatives, designed for use with systems ,mainly to drive an external bell.
One was a master size wall face plate with a transistor ringer in it, powered from a 50v feed from a system. The other was a mains driven converter ringer.
Possibly the blokes wh worked on BT systems in that era wil have more info .
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