PURPOSE: To automatically restart a system without the aid of a host computer even if a communication processor causes system-down so as to set the system to be a communicable state.

CONSTITUTION: A system-down recognition means 7 recognizes the system-down of the communication processor 2, and a restart information read means 8 reads restart information becoming necessary from a memory information file 11. A memory information development means 9 memory-develops memory data from the memory information file in the communication processor. A system starting means 6 starts again the system so as to operate the communication processor. Even if the communication processor causes system-down, the system automatically restarted. Thus, the aid of the host computer is not required.