| 摘要 |
PURPOSE:To connect easily a loop to a transmission line by providing a function checking the presence of a signal of a loop-shaped transmission line and a function transmitting a specific pattern to the transmission line to a data transmitter to constitute easily the loop at the rising. CONSTITUTION:A couple of loop-shaped transmission lines 11-14, 21-24 having the 1st system and the 2nd system of a loop data transmitter are provided with photoelectric converting circuits 30, 31. Further, a signal line control circuit 32 is connected to the respective converting circuits 30, 31 and a processor 33 and a storage section 34 are connected to the circuit 32. The circuit 32 is provided with a signal interruption detecting circuit 91, a transmission/reception circuit 92, a clock generating circuit 94, a decoder 93 and FF101, 102 and FF201-203 or the like representing the state possible for transmission and reception. Then the data transmitter is provided with a function checking the presence of the signal of the transmission line and transmitting the result, and a function transmitting a specific pattern to form the loop easily thereby connecting the loop easily to the transmission lines 11-14 and 21-24.
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