DEVICE FOR CONTROLLING TELEPHONE SUBSCRIBER CALLING SIGNAL AND DEVICE FOR TERMINATING SUBSCRIBER LINE

摘要

PROBLEM TO BE SOLVED: To reduce the overvoltage suppression circuit of a subscriber line supplying a ringing signal to a telephone set and allow a subscriber circuit storage device to suppress a high voltage at a time when a call arrives at the telephone set. SOLUTION: In this telephone subscriber calling signal controller calling to the telephone set by the ringing signal when an incoming call arrives from a subscriber line terminating device, the subscriber line terminating device is provided with a zero cross point detection circuit generating a zero cross point synchronizing signal that synchronizes with the zero potential of the ringing signal and an order transmission timing adjusting circuit controlling the transmission timing of a ringing control order that synchronizes with the zero cross point synchronizing signal and controls the ringing relay of the subscriber circuit, and makes a call-out with the ringing signal by the telephone set synchronizing with the zero cross point synchronizing signal.