| 摘要 |
PURPOSE:To improve the service without extension of equipment of an exchange system by accommodating a line circuit to a main channel network and allowing a central control circuit to control the main channel network depending on allocated position information of a trunk circuit so as to connect a telephone terminal set and a trunk line. CONSTITUTION:A trunk line selecting signal from a telephone terminal set 1 is fed to a line circuit 3 via a transmission line 2 by operating a key 1a at the outgoing of trunk line. The central controller 7 receives and detects it, controls the main channel network 5 depending of the allocated position information of a trunk circuit 9a in the network 5, connects transmission lines 4 and 10a and connects the terminal set 1 and the trunk line 11a. When an incoming is given from the trunk line 11a, a trunk circuit 9n detects the incoming and gives the information to the circuit 7. The circuit 7 reads the allocated position information of the circuit 3 accommodating the terminal set 1. Thus, a transmission lines 10n and 4 are connected by controlling selectively the network 5 so as to connect the trunk line 11n and the terminal set 1. |
