REDUNDANCY CONFIGURATION CHANGEOVER DEVICE FOR TRANSMITTER AND MONITOR CONTROLLER

PROBLEM TO BE SOLVED: To provide a flexible network by monitoring a fault state at all times and selecting and setting properly any of plural standby transmission lines depending on the fault state so as to attain simultaneous relief to faults of plural transmission lines. SOLUTION: A transmission line fault monitor section 12 always monitors a fault state of transmission lines #1 to #n and informs it to a host controller 3 and a selector changeover control section 11. Furthermore, depending on the fault state, transmission lines used for standby lines are decided among N transmission lines and designated information is set to a selector changeover control section 11 of the transmitter 1. When the designation is made by a number, the number is described in a setting data revision request byte of a maintenance control data frame of an opposite transmitter 2 as redundant configuration of standby transmission lines. Furthermore, when the designation is made by the number of lines, transmission lines with a high fault rate are checked and the standby lines are decided in high order. The transmitter 2 checks the decision based on the designation to change the redundant configuration. Thus, simultaneous relief of faults in the plural transmission lines is attained and a flexible network is obtained.