This is a very small telephone exchange attached only two ordinary Tele phones. Fully bi-directional facility with an intercom system. When a phone is in off hook condition , Exchange will detect it & send ringing pulse to other phone. When it will be picked up , the connection will be established between both phones. This will be taken place vice-versa.
 

Micro Controller   = PIC16F84A
Firmware version = 1.00
Power Supply      = 230 v

Unit developed by Achira – [email protected]