| 摘要 |
First and second optical couplers (C1,C2) are inserted in linear bus type first and second data buses (L1,L2) for transmission to right and left, respectively, by which each terminal equipment (TE1) is connected to the first and second data buses. In the terminal equipment first and second monitor pulses are generated by a monitor pulse generator (MA) at different points of time in a low-level period of a frame synchronizing signal of each frame forming data to be transmitted, by which first data to be transmitted, appended with the first monitor pulse, and second data to be transmitted, appended with the second monitor pulse, are formed and are provided to the first and second optical couplers, respectively. The optical data signals branched from the first and second optical couplers are received by a common photodetector (PD). A monitor pulse detector (MD) outputs an error flag when it detects either one of the first and second monitor pulses in the received signal. <IMAGE> |
