| 摘要 |
PURPOSE:To attain the communication between terminal equipments provided with no line switching device by setting automatically a line switch of a repeater station to the relay mode when the repeater station is in the off-state, detecting the on-operation of both connection stations at the relay mode so as to make the switching in the repeater station ineffective. CONSTITUTION:An OFF signal is detected by a repeater station power ON/OFF detector 5 when a terminal equipment of a station A being a repeater station is turned off normally, and the relay mode (B-C communication mode) is attained automatically by a control circuit 7. On the other hand, when the station A starts communication with the station B, the station A selects the A-B line of a connection line selector switch 3. In this case, the power supply state of both stations is detected by a non-repeater station power supply (B, C) ON/OFF detector 6 and only when either station or both stations are in the OFF-state, the control circuit 7 applies control to switch the line. Thus, even if the station A switches the line in error, the interruption of the B-C communication (relay mode) is prevented.
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