| 摘要 |
PURPOSE:To monitor an optical cable itself in which the main signal is transmitted by transmitting a special signal for monitoring the optical cable with the same optical cable as the main signal and discriminating the special signal. CONSTITUTION:An optical multiplexer 8 and an optical demultiplexer 9, for example, can multiplex and demultiplex the rays of light having two different wave lengths of 810(nm) and 890(nm). Consequently, in the same optical cable 1, an optical transmitting main signal S1 and the special signal S2 for monitoring the optical cable are transmitted and optical receivers 4 and 10 can receive these signals respectively separately. The optical receiver 10 judges that the optical cable is abnormal when the signal S2 for monitoring the optical cable signal S2 can not be received and outputs a signal to a monitoring output terminal 6 and therefore, the optical cable can be monitored without fail. Since the main signal is a group of several bits of the basic clock and can receive the information, the signal can detect at a high speed. |
