pulse dialling

Pulse dialing (IWV) is an older signaling method for telephones, also known as DC signaling. The pulse dialing method is used to transmit the desired telephone number to the exchange.

In this method, the dial digits on the dial keypad are represented by a corresponding number of direct current pulses, the pulse codes(IKZ). These DC pulses are generated by interrupting the loop current of the exchange battery. The duty cycle of the pulses is 60:40, and the maximum character duration is 10 x 100 ms, or one second. The dial puls es are transmitted to the telephone exchange where they are used to establish a connection. The number of DC pulses corresponds to the dialed digit.

Another method that has replaced pulse dialing is multifrequency dial ing(DTMF).