I am trying to simulate a small micro-processor controlled PABX on ISIS-Proteus...eveything seems to be OK. But can someone tell me what I can use to substitue for the telephone set which I am to use to as the hook switch and the keypad...I am thinking of simple SPST relay for the hook switch and a simple keypad for the buttons????
For accuracy you should set up a small tellephone network by using actual handsets. However, if you are unable to do so you would have to 'create' a touch tone dialer and tone decoder. Both are possible using a PIC, just Google for tone dialer with PIC micro.