| 摘要 |
PURPOSE:To ensure the normal monitor and at the same time to perform the normal loop-back when a transmission line, etc. has a fault, by monitoring how many times a specific pattern is rewritten at a monitor station until the monitor signal is sent back and then detecting the overlapped setting of a node number. CONSTITUTION:A region 3 where a specific pattern is inserted is provided in a frame format of a monitor signal transmitted from a monitor station SV. On the other hand, the specific pattern is rewritten at the node station having a number received an access to be fed to the following node station along with an answer signal. The station SV monitors how many times the specific pattern is replaced until the monitor signal is sent back. Thus the overlapped ND2, C=1 plus ND2 and C=2 of the node number are detected. |
