| 摘要 |
PURPOSE:To monitor an important fault with less alarm transfer bits by transferring more important fault information from upperstream as it is to a downstream when a fault takes place in plural relay blocks if the quality of fault information from the upperstream is sufficiently reliable. CONSTITUTION:A transfer bit identification section 2 identifies alarm information (c) of an alarm transfer bit added to a frame of an electric signal (b) converted from an optical signal (a). A fault detection section 3 detects the deterioration in the transmission line by the electric signal (b) and outputs it as fault information. An alarm generating section 4 outputs the electric signal (b) to a relay transmission line (f) via an alarm insert section 6 and an electrooptic conversion section 7 without any modification when the content of the alarm information (c) has higher priority than that of the content of the fault information (d) of its own station and the content of the information is reliable. |
