JPS6417549A - Network control unit - Google Patents

Abstract

PURPOSE:To use plural private equipments through one telephone line by detecting a calling signal from the line, serially closing the line, receiving a control signal for specifying a private equipment to be speaked, and supplying power the private equipment to call the equipment. CONSTITUTION:Since a call tone is sent through the telephone line 102 at the time of termination, the call tone is detected by a termination detecting circuit 103, a timer circuit 107 is started, a switch corresponding to the private equipment is closed, and only a telephone set 117 is directly connected to the line 102. When the telephone set 117 is unhooked under said state, normal speaking can be attained, and if the telephone set 117 is not unhooked during the previously fixed time, a timer 107 counts up the time, a switch 112 is opened by a main control circuit 111 and the telephone set 117 goes to an offhook state by a DC terminal circuit 104. After sending a response signal by a response signal transmitting circuit 106, the contents transmitted from the originating subscriber are decoded by a control signal receiving circuit 105, power is supplied from a power supply circuit 108 to an automatic answering telephone set 118, a call tone is sent from a call tone generating circuit 109 to execute normal operation by the telephone set 118.