| 摘要 |
PURPOSE:To detect a fault of a submarine coaxial cable rapidly and surely and thereby break a feeding device without delay, by branching a pilot-signal detection signal rapidly responding to the detection of the fault, so as to detect the fault and cope with the same. CONSTITUTION:A plurality of pilot signals for monitoring transmission characteristics, sent from a terminal station 24' and responding rapidly to the detection of a fault, are branched by a hybrid 26 of a home station 24 and detected by a pilot detecting device 27. Pilot-signal detection signals delivered therefrom are branched respectively by branching terminals 29 and supplied to an AND gate 31. When a submarine coaxial cable 22 is disconnected completely, each pilot signal is not detected and the output of the gate 31 is inverted to a low level. Thus the fault is detected rapidly, a feeding device 30 is deenergized through a driving circuit 32, and thereby a supply of constant current to the relay 21 of the cable 22 is stopped immediately without delay. In this way, the impression of surge current or the like on an apparatus such as a communications apparatus can surely be prevented. |
