Circuit arrangement for a remote speech direction changes station with a surge arrestor, in particular remote speech direction changes tat ions with keys selection

摘要

An excess voltage arresting circuit (a, GU2, K1, K2, b) with already existing contacts with different excess voltage resistances (GU1, GU2, K1, K2) does not pass through any further components or circuit elements. The above contacts are in fact two cradle contacts (GU1, GU2) connecting to the line the ringer or telephone instrument, and two keyboard contacts (K1, K2). The excess voltage resistance of the contact (GU1) connecting the ringer to the line is greater than that of the other contacts. When the circuitry is in dialling operation the cradle contacts (GU1 & 2) are operated as in speech operating state. During the transmission of dialling pulses one contact (K1) is open while the other (K2) is closed.