Telephone Call Recording Circuit Circuit


Posted on Dec 21, 2012

The dc voltage present on a telephone line is usually around 45 to 50 V on-hook and 6 V off-hook. This circuit uses This drop in voltage to activate a relay. The relay controls a cassette tapeTecorder.


Telephone Call Recording Circuit Circuit
Click here to download the full size of the above Circuit.

Audio is taken off through a network to the microphone input of the cassette.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Stepper Motor controller with HC11
Single-chip-frequency-doubler
Designing A Li Ion Battery Charger with Load Sharing MCP73837
water level indicator using 7 segment display
Ultrasonic sensors apply to parking sensor system
80M CW QRP rig
SUPPRESSED CARRIER MODULATOR
Brushless motor rotor a stator and a drive circuit



Top