| 摘要 |
PURPOSE:To make it possible to sustain a constant propagation delay time between a plurality of electric stations even if the communication lines are switched. CONSTITUTION:Upon detection of disturbance through disturbance detecting circuit 27B1 or 27B2, a control circuit 30B switches its communication line based on a control signal for selecting other normal communication line and the controller 30B delivers a switching command to a counterpart electric station. The communication line is then switched based on a switching command delivered from the counterpart electric station in response to the aforementioned switching command. |
