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audioguru
Nobel Prize Winner
Canada
4218 Posts |
 Posted - Feb 10 2008 : 4:56:32 PM
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Yes, the output will be high at rest and will be low during each ring.
For local calls, my phone line rings for 2 seconds then has a 4 seconds pause before the next 2 seconds of ringing.
For long distance calls the line rings differently:
I think it rings for half a second then a half a second pause then rings for half a second again then a few seconds pause before it rings twice again. The 10k resistor and 100uF capacitor might not integrate these rings properly.
This circuit will feed the high input resistance of a micro-controller, not the low resistance and high input current of old fashioned TTL. |
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Ringing Phone Light Flasher
