| 摘要 |
Test equipment for testing an optical fibre transmission line which is operated in bi-directional wavelength multiplex mode, the line or system, having sending and receiving paths each of which has a high frequency transmitter 7, 7', an electro/optical converter 6, 6' an opto/electrical converter 3, 3' and a high frequency receiver 5, 5'. In association with the high frequency transmitters 7, 7' and electro/optical converters 6, 6' there is provided a pair of start circuits 2, 2' controlled by key or test switches 1, 1' which when one is closed to initiate a test cause a continuous signal to be transmitted along one path this being detected at the receiving end of that path and utilized to initiate transmission of a similar signal along the other path. The test sequence can only be initiated when no data is being transmitted and precautions are taken to prevent the system being maintained permanently in the test condition. <IMAGE> |
