| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit switchover device capable of preventing unnecessary switchovers caused by maintenance or transmission line delay differences, regardless of the configuration of a redundant system. SOLUTION: An SDH(synchronous digital hierarchy) interface unit 110-1 identifies the type of a redundancy configuration and monitors received SDH signals, and if it detects an error, it generates faulty trunk alarms 12w and 12p according to the content of the error. An APS(automatic protection switch) control unit 101-1 sets a take-in protection time according to the content of the redundancy configuration, and conducts switchover decision by faulty trunk alarms 12w and 12p taken in based on the take-in protection time and by the switchover information related to SDH signal switchover. An online control unit 106 outputs a switchover signal 22, which is multiplexed with insertion of an identification code of each circuit. A system selection unit 111-1 extracts a switchover signal 22 matching a unique circuit identification code and selects either of the active system or the standby system. A transmission circuit 116-1 outputs the selected signals.
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