| 摘要 |
PROBLEM TO BE SOLVED: To prevent a transmitting signal from being transmitted from a light- emitting element during reception of a receiving signal by a light-receiving element, even when a malfunction occurs in a light-emitting element drive circuit or a transmission control part. SOLUTION: A control signal 16 is inactivated, and a switch 10 is opened when receiving data 14 is detected by a light-receiving detecting circuit 6. Therefore, since a drive signal 15 is not inputted in the light-emitting element 3 and the transmitting signal 13 is not outputted from the light-emitting element 3, even when a drive signal 15 is outputted from a light-emitting element drive circuit 9 by the malfunction of the light-emitting element drive circuit 9 or the transmission control part 7, reflected light is not generated in a connecting point 5 and the receiving signal 12 is not interfered. |
