| 摘要 |
Disclosed is a redundant data transmission and storage system employed within a telephone message metering system. Information concerning local subscriber usage is transmitted over one of two redundant data paths where each data path is capable of independent operation. The selection of which data path, if any, is enabled in the active state is made by control networks, one associated with each data path. Under alarm conditions, the data path initiating the alarm causes its associated control network to be in the inactive state. The other control network, absent an alarm in its own data path, senses the inactive state of the other data path and enables its own data path in the active state. The control networks are responsive to alarms having different priorities. Some alarms cause a transfer of the active state while, under particular conditions, others do not.
|
