COMMUNICATION APPARATUS OF MOVING BODY

PROBLEM TO BE SOLVED: To cut off the electric connection of a controller of a moving body such as construction machines from a power source always after completely ending a present process in the controller. SOLUTION: Before a time t1, an engine key switch 64 is set on to turn on an internal switch 802, thereby electrically connecting a controller 54 with a power source 63. If the key switch 64 is set off at the time t1, a self hold signal CT at logic level 1 continues being outputted while the controller 54 is executing a process. Hence, the switch 802 holds the on-state to keep the electric connection of the controller 54 with the power source 63. When the controller 54 ends the process at a time t2 lapsed from the time t1 after setting off the key switch 64, the self hold signal CT turns to logic level 0, this causing the switch 802 to set off to cut off the electric connection of the controller 54 with the power source 63.