phone busy circuit

Posted on Feb 7, 2014

Have you ever been using the modem or fax and someone else picks up the phone, breaking the connection Well, this simple circuit should put an end to that. It signals that the phone is in use by lighting a red LED. When the phone is not in use, a green LED is lit. It needs no external power and can be connected anywhere on the phone line, even mo

phone busy circuit
Click here to download the full size of the above Circuit.

unted inside the phone.

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