| 摘要 |
PURPOSE:To switch automatically all transmitters to stand-by systems, by identifying a break of a signal at the input side of an operational system, and supplying signal break data to the output side of the operational system, and switching it to a stand-by system. CONSTITUTION:The photoelectric converting circuit 30 of a data transmitter 1 holds a data line 51 at ''1'' in response to the breaking of the 1st loop system transmission line 14. A transmission line control circuit 32 sends out an interrupt signal to a clock interrupt signal line 82 in response to said data. Then, a processor 33 sends data and a write pulse to the circuit 32. The circuit 32 places the transmission line 14 in a stand-by state in response to those data and a pulse to place transmit clocks and data of the 1st loop system transmission lines 11- 14 in off states. Consequently, the transmitter 1 is connected to the 2nd loop system transmission lines 21 and 22. A transmitter 2 operates similarly to the transmitter 1 and is connected to the 2nd loop system transmission lines 22 and 23. Similarly, transmitters 3 and 4 are connected to the 2nd loop system transmission lines 21-23 in order. |
