| 摘要 |
PURPOSE:To supervise a transmission line without the provision of other system for supervision by sending a fault display signal from an intermediate repeater. CONSTITUTION:When a transmission line 72 is disconnected, for example, a fault display signal with (0), (1) alternate pattern is sent from the intermediate repeater 30 to a terminal station repeater 40, and a fault signal of (0), (1) alternate pattern is detected by a (0), (1) alternate signal detection circuit 41 in the terminal station repeater 40. The period of the alternate signal is made different little by little at each intermediate repeater, and the terminal station repeater locates the intermediate repeater by observing the period. Even when a transmission line supervisory signal is superimposed on the transmission signal, a transmission line supervisory equipment 45 for the terminal station repeater and a transmission line supervisory equipment 35 for the intermediate repeater are communicated, and the transmission line supervisory equipment 45 supervises the transmission line. Further, an alternate pattern detection circuit 41 in the terminal station repeater 40 detects the fault display signal sent from the intermediate repeater to make alarming from the terminal station repeater 40. |
