JPS6469146A - Monitor calling system - Google Patents

Abstract

PURPOSE:To give a suitable instruction to a monitor requester without being noticed by a monitor object person by permitting the bidirectional call of a monitor requester and a monitor object person, and the monitor requester and an adviser and permitting an one-way call from the monitor object person to the adviser. CONSTITUTION:When an extension telephone set 2, which is an adviser, executes the operation of the monitor start in accordance with the instruction of the advice request of the extension telephone set of a monitor requester, the control data of the monitor instruction are sent from a subscriber circuit 4 connected to the extension telephone set 2 of an adviser through a control data bus 6 to a central control circuit 11. The central control circuit 11 sends the control data to a trunk control circuit 9 for monitor calling and instructs a trunk circuit 8 for monitor calling. At such a time, the one-way calling can be obtained in which the bidirectional call path between the extension telephone set 1 and the extension telephone set 2 is permitted, a call path passes through only in the call direction from a line wire telephone set 3 to the extension telephone set 2 between the extension telephone set 2 and the line wire telephone set 3 and does not pass through in a reverse direction.