| 摘要 |
PROBLEM TO BE SOLVED: To immediately discriminate the cause of the disconnection of an in-use line in such a case. SOLUTION: If a line is disconnected during optical spatial transmission, a signal input part 10 and a signal output part 24 are connected first to check whether or not the signal input part 10 and signal output part 24 in this device M get out of order. When there is no fault, luminous flux is looped back in this device M to check whether or not an electrical-to-optical conversion part 15, an optical-to-electrical conversion part 23, and an optical system in this device M get out of order. When there is no fault, it is evident that this device M has no problem. Then luminous flux is looped back in an opposite-side device including the atmosphere for transmission to this device M and if a fault is found, it is evident that the fault is caused by the atmospheric state in transmission or optical axis deviation between transmit and receive lights. If there is no fault, the optical-to-electrical conversion part 23 and the electrical-to-optical conversion part 15 of the opposite-side device are connected to check whether or not there is a fault from their loop-back state. If a fault is found, it is found that some of the optical-to-electrical conversion part 23, electrical-to-optical conversion part 15, and optical system of the opposite-side device caused the fault. If no fault is found, it is evident that a signal input part 10 or signal output part 24 of the opposite-side device causes the fault. |
