| 摘要 |
PURPOSE:To discriminate a fault of an optical fiber cable and a fault of a subscriber unit separately and to discriminate the fault of the each subscriber unit and the fault of each subscriber in-unit circuit. CONSTITUTION:This system os provided with a center station unit 1 having a signal processing circuit 10, an optical transmission circuit 11, a photocoupler 12, an optical reception circuit 13, a low frequency indentification circuit 14 and an alarm circuit 15 which process transmission of an optical signal of an outgoing station side and reception of an incoming optical subscriber signal and an optical monitor signal, indentify the presence and the type of both signals to discriminate the fault of each of optical fibers 2, 4-1 to 4-n and subscriber units 5-1 to 5-n thereby outputting an alarm on the occurrence of a fault and plural subscriber units 5-1 to 5-n. Further, an optical reception circuit 51, a signal processing circuit 52, and optical transmission circuit 53 and a low frequency generating circuit 54 which process the reception of an outgoing station transmission optical signal and send the incoming optical subscriber signal and the optical monitor signal are provided. Furthermore, a photocoupler 3 branching the outgoing station transmission optical signal to the subscriber units 5-1 to 5-n and coupling the incoming optical subscriber signal from the subscriber units 5-1 to 5-n and the optical monitor signal. |
