| 摘要 |
PURPOSE:To inexpensively realize a self-diagnostic function by detecting a light receiving output voltage when only a leaked light from a light emitting means directly to a light receiving means is received so as to omit excess optical fiber signal lines for diagnosis. CONSTITUTION:When a control section is received by an optical transceiver 1, a drive circuit 21 stimulates a light emitting element 22 based on a control signal from a light emitting control circuit 20. The light is sent to a peripheral equipment via an optical branching coupler 105 and an optical fiber signal line 4, and simultaneously a leaked light is received by a light receiving element 32 via optical paths 51, 52. When a light emitting means 2 is deteriorated and the intensity of the stimulated light is reduced, the intensity of the leaked light is educed. In this case, when the light passing through the line 4 is not in existence, an output voltage VO of the light receiving means 3 gets lower than a 2nd reference voltage TH2 of a comparator 8. As a result, an abnormal signal is outputted from the comparator 8 and the signal and a light emitting signal S20 from the circuit 20 are multiplexed and a logic discrimination circuit 7 provides an output of a signal representing a fault. |
