| 摘要 |
PROBLEM TO BE SOLVED: To ensure a feeding path to other cables on the occurrence of a fault in a cable. SOLUTION: An optical cable TRUNK (BRANCH1, BRANCH2) is connected respectively to a terminal A, (B, C). A relay K1 is activated by supplying a negative current to the circuit from the BRANCH1 while the BRANCH2 is kept open and the TRUNK connects to ground. Thus, the BRANCH2 is disconnected from the circuit and connects to ground. Then a positive current is supplied from the TRUNK to feed power to both ends of optical cables connected to the TRUNK and the BRANCH1. Then a relay K3 is active by supplying a negative current to the circuit from the BRANCH2 while the TRUNK is kept open and the BRANCH1 connects to ground to disconnect the TRUNK and to connect the BRANCH1 and BRANCH2 to ground at a ground E2. Thus, power is fed to each line from one side. |
