| 摘要 |
PROBLEM TO BE SOLVED: To monitor the optical transmission line switched or switched back without providing a monitoring optical signal source in the system or on the outside of the system. SOLUTION: When an optical signal monitor section 108 under service in an optical crossconnection system 100 confirms occurrence of a trouble on an optical transmission line under service, a switch control section 103 performs following control. An optical switch section 101 under service connects 'input 1' to 'output 2' and connects 'output 1' to 'input 2' A second output select section 116 selects the 'output 2' of the optical switch section 101 under service. As a result, communication data between opposite stations is delivered to a preliminary optical transmission line. On the other hand, a preliminary optical switch section 102 connects the 'input 1' optically to 'output 3' and a third output select section 117 selects the 'output 3' of the preliminary optical switch section 102. Consequently, an optical signal delivered to the optical transmission line under service is monitored at the optical signal monitoring section 108 under service in the system 100 of the opposite station and recovery of trouble on the optical transmission line under serviced is monitored. |
