PURPOSE: To realize the control for all systems with just one order, by providing the master address which is common to all units in addition to the self-address which is proper to the unit used normally.

CONSTITUTION: The information sent in via system bus 7 and including the address information is received at information receiving part 41. And for the address information of the information, the comparison is given at adeess information comparison parts 44 and 45 between self-address 43 proper to the unit and master address 42 common to all inter-system communication control units. Thus the comparison coincidence signal between both addresses is supplied to control part 47 via OR circuit 46. Information processing part 48 can perform the processing for the information which is sent in by the self-address proper to the normal unit as well as the information which is sent in by the master address of emergency time of the system. As a result, the all systems can be operated at one time by the master address.