| 摘要 |
PURPOSE:To prevent an interference in a control system from occurring by connecting respective satellite terminal equipments with a connecting wire, and, when one terminal equipment receives an optical signal transmitted from a transmitter, disabling the other terminal equipments for the reception of an optical signal. CONSTITUTION:When an optical signal is transmitted from the transmitter 8, in the satellite terminal equipment 21, the signal received by a photodetector 11 is converted to an electric signal, and an amplifier 12 and a tuning part 13 together execute the reproduction of the signal. In case other satellite terminal equipments 22 and 33 do not receive a signal or a satellite stop switch 9 is not turned on, the f-point of the collector of a transistor Tr1 comes to H, and the signal goes through an AND gate G2 and inputted to a leading detecting circuit 19. The signal then is inputted to the set input S of an RS flip flop 16, and an H-level signal is outputted from an output terminal Q. The said signal turns the transistor Tr1 on to let its collector come to L-level. And thus the potential of the connecting wire 5 is shifted to an L-evel through terminals T1 and T2. As a result the operation of other satellite terminal equipment 2 is stopped.
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