OPTICAL TRANSMISSION DEVICE AND METHOD FOR CHECKING TRANSMISSION IN AN OPTICAL TRANSMISSION DEVICE

摘要

The invention relates to a method for checking transmission in an optical transmission device comprising optical fibers for transferring useful optical signals between signal sources and signal drops (S/D), wherein useful optical signals are coupled into the optical fibers or are coupled out of said fibers, and can be deviated along substitute paths on the nodes (OCC) of the transmission device. Control signals (LS) for at least one useful signal are transmitted in each optical fibber between the signal sources and the signal drops (S/D) in addition to the nodes (OCC) in both directions. The presence of control signals (LS) is verified. If no control signal (LS) is detected in either direction, emission of a control signal (LS) in the opposite direction is prevented. This enables an abnormality to be detected on both sides of a line and optionally sets off an alarm or results in switching to a substitute path.