STATION LOOP CONTROL ARRANGEMENT FOR TELEPHONE SWITCHING SYSTEM

摘要

STATION LOOP CONTROL ARRANGEMENT FOR TELEPHONE SWITCHING SYSTEM The present invention relates to a telephone line circuit. The circuit comprises a line relay, a pair of tip and ring conductors for connecting the line relay to a telephone set and a ringing control relay having a set of transfer contacts. The transfer contacts include a make contact for normally applying ringing current to one of the pair of tip and ring conductors and a back contact for disconnecting the ringing current from the line relay. An operating unit is provided for operating the line relay during a predetermined interval of time when ringing current is not applied to the make contact.