POWER SUPPLY SYSTEM OF CUSTOMER STATION CONTROLLER

摘要

PURPOSE:To allow an emergency communication while a connection with a customer station device is maintained by supplying station power to digital customer station equipment when the commercial power supply is cut off, and transmitting the actuation of the customer station equipment to a station and sending a switch signal to a digital signal line. CONSTITUTION:The off-hook state of a digital telephone set 2 (when the loop of the line 26 of a customer station equipment interface R is closed) is detected by an actuation detecting circuit 4 and reported to a control part 16. The loop of a network interface R line 24 is held by an actuating circuit 23 under the control of the control part 16. Signal path switch circuit 35-38 are switched from signal transmission lines 33 and 34 to sides of the control part 16 according to the commercial power supply detection of a power failure detecting circuit 30, and a digital signal is transferred through the control part 16 which operates with electric power supplied from a power supply circuit 6 on the basis of the commercial power source 17.