Telemonitor For Recording Phone Calls


Posted on Sep 7, 2012

This circuit switches a tape recorder via PL2. When on-hook, D5 conducts, turns on Ql, and cuts off Q


Telemonitor For Recording Phone Calls
Click here to download the full size of the above Circuit.

2. Ringing voltage will also cause D5 to conduct; C2 and CI should be rated 150 V or higher. When phone is off-hook, the 10 V or so present on the line will not break down D5, and therefore Ql is off and Q2 is biased on. PL2 connects to the remote control jack on the tape recorder. Audio is taken from PL1. Caution: Use either a battery tape recorder or an FCC/CSA/UL-approved ac adapter-powered tape recorder. This precaution is to avoid inadvertent 120 Vac on the telephone line.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Digital thermometer with LED / LCD display
    10 to 1000 MHz Oscillator circuit with RF2506
    LA4440 audio amplifier circuit design electronic project
    High Resolution 24-bit Data Acquisition System instrument-control
    LM2002 Series 8W audio power amplifier circuit
    Car battery charging circuit diagram



    Top