SKYDDSANORDNING FOR EN ABONNENTTELEFONAPPARAT

摘要

A protection circuit for a subscriber's telephone set which comprises a resistor applied in series with the subscriber's line to which resistor a threshold device is connected in parallel, a network being provided which comprises the control input and which is connected between the subscribers' lines while the output of the threshold device is connected to the control input to switch the normally high impedance to a low impedance when the threshold voltage of the threshold device is exceeded by the voltage across the resistor.