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Telephone Ring Count Circuit

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Suraj143

Active Member
I'm building a telephone ring counter circuit.Need to check the attached circuit.

I have two questions

1)How many pulses will comes out per one ring from opto output?
2)what are the voltages in the telephone line ? When idle -48V DC & when rings 90V AC?
 

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audioguru

Well-Known Member
Most Helpful Member
Canadian telephones ring with a 20Hz frequency. We do not know the frequency used in your country. Some telephone companies ring long distance calls with a different cadence (ring ring pause, ring ring pause).
Some telephone systems ring with 90VAC RMS on top of the 48VDC, others have different voltages.
 
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