FAULT INFORMATION SYSTEM

PURPOSE:To inform the fault of a host computer system to a terminal, and also to keep the terminal at a state possible to communicate, by generating and transmitting a transmission telegram representing the fact that the fault is generated in the host computer system, to a reception telegram from the terminal during a fault state period. CONSTITUTION:At the time of detecting the fault of the host computer system 11 by a communication control part 121, the fault of the host computer system 11 is informed to an independent operation control part 122. The independent operation control part 122 keeps a pre-communication processor subsystem 12 at an indcpendent operating state. Meanwhile, the independent operation control part 122, when receiving the information of reception of a telegram from a terminal communication control part 123, disposes of a received telegram, and generates a host fault telegram representing the fact that the fault is generated in the host computer system 11, and informs the host fault telegram to the terminal communication control part 123. The terminal communication control part 123, when receiving the host fault telegram from the independent operation control part 122, transmits the host fault telegram to a terminal 15 which receives the telegram first.