NETWORK CONTROLLER

PURPOSE:To provide a call priority function, by monitoring the usage state of a telephone line corresponding to a call request signal transmitted from a terminal device, and connecting the telephone line to the terminal device when the line is not busy. CONSTITUTION:When the call request signal from terminal devices 3, 4 is incoming, only when the line 1 is dicriminated that it is in the idle state based on an output signal of a line monitor circuit 107, a network controller 100 closes the DC loop of a subscriber telephone line 1 under the disconnection state of the line 1 with switching circuits 101, 102 with a telephone set 2. Further, a call reception signal is transmitted to the terminal device 3, 4 and a selection signal is transmitted to an exchange based on the selection information given from the terminal devices.