| 摘要 |
PURPOSE:To find out the detection of the cut off of an optical fiber in its early stages, by sending a signal from a center station side periodically, and supervising the return of a response signal from a subscriber. CONSTITUTION:The signals are outputted from a timer 4 and a signal generation circuit 3 so as to sent the signal periodically into the center station unit 1 of an optical subscriber system, and an optical fiber 7 is transmitted by driving an optical transmission/reception circuit 2 on the optical subscriber center station side. An optical transmission/reception circuit 9 in a subscriber unit 8 receives a transmitted signal, and detects the signal, and outputs the response signal from a response signal delivery circuit 10. The response signal is transmitted as 10 9 7 2, and is confirmed at a response signal detection circuit 5. Since no response signal is returned when the optical fiber is cut off, it is possible to supervise the optical fiber of a subscriber line by issuing alarm from an alarm circuit 6. |
