| 摘要 |
PURPOSE:To discriminate and to locate in which of an up-line or a down-line a fault is generated, by inserting code error correcting circuit into a turning- back transmission line. CONSTITUTION:As for a fault search signal which is loopbacked by switching signal switching circuits 8, 9, an error of a code rule which has been generated in a down-transmission line 2 or a repeating board 6 is corrected by a code error correcting circuit 13. Accordingly, a fault search signal measuring instrument 5 of a station 1 can detect in which repeating point, and in which of a down-line or an up-line a fault is generated, by measuring an error of a sending-out pattern of the fault search signal and an error of the code rule. That is to say, in case the fault is generated in the down-line, the error of the sending-out pattern is detected, but the error of the code rule is not detected. Also, in case the fault is generated in the up-line, both the error of the sending- out pattern and the error of the code rule are detected. |
