| 摘要 |
<p>PROBLEM TO BE SOLVED: To appropriately process when a synchronization message or clock reference can not normally be detected about the selection technique of a clock in a synchronous network like an optical communication network, etc. SOLUTION: A synchronization message detecting means 104 detects a synchronous message 105 from a line signal 103 which is received from a line 101 by a line terminating means 102. A synchronization message processing means 106 controls whether or not clock reference that is received from the line 101 is selected as active reference based on a quality level that is shown by the message 105, and in such cases, when a mounting state detecting means 107 detects that the means 104 is not mounted, clock reference that corresponds to the message 105 which is detected by the means 107 is not selected as active reference.</p> |
