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

    Super Class-A 30W Amplifier
    30 Watt FM Linear amplifier with Mosfet BLF245
    Precision battery voltage monitor
    Broadcast Band Booster
    Bunch connect the compensating type UPS cascade converter in parallel to study
    internal resistance tester for
    DIY Fisher 800b into a mic pre
    RF Module Interfacing Circuit Example
    FET high input impedance wideband amplifiers



    Top