| 摘要 |
<p>PURPOSE:To attain changeover to an optimum standby system by inserting a monitor cell to an incoming line at a changeover to a standby system and Selecting the standby system when a coincident signal of the monitor cells extracted from both the active system and the standby system is detected. CONSTITUTION:The system is provided with a distribution line 3 distributing an input cell of an incoming line to a channel for the active and standby system, an insertion circuit 5 inserting a monitor cell for switching control to the incoming line, extraction circuits 20, 21 extracting the monitor cell from the outputs of both the systems and a changeover circuit 4 selecting one of outputs of both the systems as an output of the active system and connecting it to an outgoing line. Then when the standby system is to be selected, a monitor cell is inserted to the incoming line, and the system is selected to the standby system after the coincidence signal of monitor cells extracted from both the active and standby systems is detected. The system is selected to the standby system by using the coincidence signal of the monitor cells extracted from both the active and standby systems in this way to attain optimum system changeover.</p> |
