Circuit arrangement for connecting the speech circuit or the dialling circuit of a push-button dialling telephone set to the connection line

摘要

In a circuit arrangement for connecting the speech circuit or the dialling circuit of a push-button dialling telephone set to the connection line, switching errors caused by mechanical vibrations or shocks are prevented by using a high-sensitivity monostable relay as the changeover relay, to which a holding circuit containing a storage capacitor is allocated which supplies the excitation winding of the changeover relay with current for the duration of the dial pulses and which is in each case recharged from the connection line in the no-pulse periods.