Please guide me about telephone exchange system

[Tauqeer]

telephone exchange

hello
please guide me that when a telephone receiver is picked up when it is ringing why high ringing voltage (e.g.90v) do not affect the remaing circuit

 

[pranam77]

Re: telephone exchange

hello
please guide me that when a telephone receiver is picked up when it is ringing why high ringing voltage (e.g.90v) do not affect the remaing circuit

The high voltage exists only till a load is connected to the lines. As you lift the handset, the cradle switch connects the regulator section across the lines which acts as a load which is then detected by the exchange, and the ring signal is cut off...Cheers