| 摘要 |
PURPOSE:To quickly switch a duplex MODEM on a substation side to a standby MODEM side without man power, by automatically switching a change-over switch on the substation side which switches the currently used MODEM to a standby MODEM by using a switching signal transmitted from a main station. CONSTITUTION:Since data communication of a substation 3 becomes impossible when the currently used MODEM 31 becomes faulty, the CPU 11 of a master station 1 catches this as a transmission error and informs the operator of the main station 1 of the occurrence of the transmission error. The operator of the master station 1 manually switches a change-over switch 13 to a remote controller 14 and sends a switching signal from the remote controller 14 to a change-over switch control section 36 through a communication circuit 2 by operating the remote controller 14 so as to cause the controller 14 to produce the switching signal which switches the change-over switches 34 and 35 of the substation 3 to a standby MODEM 32 side. Upon receiving the switching signal, the change-over switch control section 36 outputs change-over switch driving signals to the change-over switches 34 and 35 and switches these switches to the standby MODEM side.
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