| 摘要 |
PURPOSE:To specify the node in the consecutive transmission state. CONSTITUTION:A management node 2 and general nodes 3,4 are connected in a star form through an optical fiber and an N:N passive optical star coupler 1. For example, when an optical transmission section 12b of the node 3 is faulty and reaches the consecutive transmission state, a detection means 16 of the management node 2 detects the consecutive transmission state and a 2nd optical transmission section 17 sends a command for specifying a fault node to a reception optical fiber 14a. It is received by the nodes 3, 4 through transmission optical fibers 13b, 13c while a light source of each of the optical transmission sections 12b, 12c as a light receiving device. In the case of the command to its own node, the nodes 3, 4 returns a response to the management node 2. Since the node 4 is normal, the response signal and the consecutive transmission signal collide with each other, the management node 2 detects the collision of the signals or the response from the node 4 is detected and the node 4 is discriminated to be normal. Since the signal collision and the response from the node 3 are not detected against relevant command, it is discriminated to be faulty. |
