| 摘要 |
PURPOSE:To reduce the circuit breakdown time and to improve the efficiency of data transmission, by generating a fault signal from one of two computers when a circuit switching end signal is not received within a prescribed time after a circuit switching command is transmitted. CONSTITUTION:Circuits 31 and 32 are provided between CPU1 and 1', and circuit switches 5 and 5' are set across the circuits 31 and 32. These switches are switched to the circuit 31 or 32 after receiving a switching command of channels CH41 and 41' of the CPU1 and 1' respectively. Now, the CPU1 recognizes a fault earlier than the CPU1' and transmits a circuit switching command to the CPU1'. Then the CPU1' of the receiving side sends a circuit switching answer telegram to the CPU1 and, at the same time, supplies command to switch the switch 5' of the own station side. Then the CPU1' sends the circuit switching answer telegram to the CPU1 when the switching is over. If no answer telegram is sent from the CPU1' although a prescribed time elapses after the CPU1 transmitted the telegrams in block unit, an alarm of fault is outputted to the own station side to finish the operation. |
