DCII 10.10.08
Digital Communications II starts today. I'm blogging links to sites about things I mention in passing.
Talking Telephone Numbers
Party Lines
Strowger
voltage of ringing - as asked: 90v AC, frequency 20-25Hz.
(28 volt I mentioned is the pulse in the exchange to drive the rotary electro-mechanical relay, not the ringing - and was a UK analogue post office standard.
Talking Telephone Numbers
Party Lines
Strowger
voltage of ringing - as asked: 90v AC, frequency 20-25Hz.
(28 volt I mentioned is the pulse in the exchange to drive the rotary electro-mechanical relay, not the ringing - and was a UK analogue post office standard.
posted by clog at 2:30 AM
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