Telephone Remote Control

Discussion in 'The Projects Forum' started by eprasadg, Oct 2, 2012.

  1. eprasadg

    Thread Starter New Member

    Jul 28, 2012
    My Project is to control the household equipment/s through land line phone. It consists of following (circuit attached). I wired the circuit connected the incoming landline wire and 5V DC supply and called the no. The green LED is blinking as the phone is ringing but circuit does not respond ie it should behave as if phone at remote end is lifted with melody coming from UM66.
    I am getting supply at output of 3140e.
    Instead of CM8870 i have used MT8870DE.
    Members Plz Help!
  2. absf

    Senior Member

    Dec 29, 2010
    When ringing is detected by IC1 and IC2, a signal would be sent to T2 BC547 and it would conduct thus tripping the ring current. Are you getting any bias voltage on the Base of T2 during ringing?

    May be your T2 is open circuit....The ring current voltage can be as high as 100V ac....

    Last edited: Oct 2, 2012