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Telephone Ring Count Circuit

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by Suraj143, Jul 26, 2017.

  1. Suraj143

    Suraj143 Active Member

    Joined:
    Jan 11, 2007
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    Location:
    South Mald Isld
    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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    Last edited: Jul 26, 2017
  2. audioguru

    audioguru Well-Known Member Most Helpful Member

    Joined:
    Mar 16, 2004
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    Location:
    Canada, of course!
    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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