| 摘要 |
PROBLEM TO BE SOLVED: To easily disconnect a fault part by looping an approach line corresponding to an applying channel at a base station side, transmitting/receiving prescribed data from a control station with the loop and collating transmission data with reception data. SOLUTION: The approach line 13 is made into a loop forming state by the change-over of relays 5-1 and 5-2. When a previously set path is formed and prescribed data are transmitted from a line control device 7, the loop is formed at a base station 2 side so that the transmission signal of a self station is received in a line controller 7 with a path forming part 8 and the approach line 13 at the time of no fault. Unless transmission data are normally received, path formation is changed and data are exchanged again. Unless it is received after that, an approach line fault is judged. In the meantime, it is judged that a substrate which is used at the time of last time path formation is the fault when normal ending is executed after changing the path. |
