| 摘要 |
PURPOSE:To prevent a system from being shut down owing to misoperation by providing system constituent equipment with a preblocking function which powers off the system after discriminating that a circuit is not in use. CONSTITUTION:A discriminating mechanism 8 for the in-use state of the circuit outputs a signal only when communication circuits 5, 6, and 7 are all off and through a power supply control switch 10, a power supply control part 9 placed previously in an operation readiness state is put in operation to power off a CPU1. For example, when terminal devices 2 and 3 finish operations and are powered off and only a terminal device 4 is in operation, an operator think erroneously that all the terminals finish their operation and then turns off the power supply switch. In this case, said discriminating mechanism 8 discriminates the in-operation state of the communication circuit 7 of the device 4 and makes the power-off operation of the CPU1 ineffective, so the operation is carried on to maintain the data transmission and reception of the device. |
