MULTIPLEX COMMUNICATION SYSTEM

PROBLEM TO BE SOLVED: To provide a multiplex communication system which can avoid complete depleting of a battery can be prevented, by surely switching the node into a sleep mode, even when any node does not sleep due to a fault or the like. SOLUTION: In the multiplex communication system wherein a plurality of nodes mutually communicate via a communication line, each of nodes in a wake-up state sets itself not to wake up by the start signal from the other node (S30) when the drop of a battery voltage is confirmed (S20: YES), stops transmitting the start signal to other nodes and further switches itself into the sleep node (S50). Thus, the entire system can be transferred into the sleep mode and the battery can be prevented from being dead without adding a hardware circuit such as a power supply cut-off relay. COPYRIGHT: (C)2005,JPO&NCIPI