| 摘要 |
PURPOSE:To maintain the high reliability of a central processor in an economical way, by adding a small-scale secondary centralized controller to a main centralized controller that gives the centralized control to the central processor having a redundant constitution. CONSTITUTION:A call applied to an electronic switchboard is processed via a channel system SP that is controlled by a central processor CP. The reliability of the processor CP is increased by forming a queuing redundant system with CPU0 and CPU1 having an input/output device IO respectively. Both the CPU0 and CPU1 are connected to a centralized controller SVP0 to receive the centralized control. In addition, a secondary centralized controll controller SVP1 contains only the initialization and fault countermeasure functions which are indispensable to the operation of the processor CP. When a fault is detected at the controller SVP0, a changeover relay AL is driven to connect the CPU0 and CPU1 to the controller SVP1 for the centralized control. The controller SVP1 incorporates the functions indispensable to the operation to give no effect to the operation of the processor CP. |
