| 摘要 |
PURPOSE:To reduce the cost through the selection to the spare transmission line at the selective station at the both ends of set section, in the selection to the spare transmission line. CONSTITUTION:Stations B, C are merely passing stations, and relay transmission is made with the relay transmission unit 6BX because the transmission line is not connected to the selector switch at station B, and relay transmission is made at the station C with the relay transmission unit 6CX. Since the station in which the transmission line X is connected to the selector switch is A and D station, the transmission line X is selected to the spare transmission line S between the stations A and D. If the transmission termination station 4AX detects a failure, signal is transmitted to the selective control station 3A and the failure transmission number X is fed to the station D via the stations B and C. The selective control unit 3D of the station D selects the selector switches 2D and 2A simultaneously with the selection control unit 3A to select the transmission line X to the spare transmission line S. |
