TRANSMISSION LINE CHANGEOVER SYSTEM AT FAULT OF MULTI-ADDRESS COMMUNICATION

PURPOSE:To attain high reliability of a network system for multi-address communication by providing a table monitoring a live/dead state of all nodes, a program to send a life report and a program receiving the life report and selecting a transmission line according to a transmission line changeover command to each node. CONSTITUTION:When a fault takes place in a main system transmission line 3, a configuration control program 11 in operation periodically detects it by monitoring a node generating monitor table 12 and informs dead recognition message of a node through a slave system transmission line 4 in a way of multiple address. A dead recognition reception program 25 receiving the dead recognition message discriminates it as a fault of the main system transmission line 3, switches the transmission line from the main system transmission line 3 to the slave system transmission line 4 and informs a life report message of its own node including a transmission line changeover command in a way of multiple address and a life report reception program 14 of other node switches the transmission line. Thus, a user message transmission program 19 uses the slave system transmission line 4 to implement multi-address notice. Thus, high reliability is attained.