| 摘要 |
PURPOSE:To prevent congestion due to an invalid process of a processor, by supplying busy tone without discriminating a state through a processor which stores the connection call to a specific subscriber or a specific trunk line in case such calls concentrate. CONSTITUTION:The contents of a memory 25 for all subscriber lines are copied to a common subscriber memory 4. For instance, an incoming is detected by a trunk line 7 stored in a trunk line processor 3 and reaches a subscriber 1' stored in a subscriber processor 2. In this case, an access is immediately fed to the memory 4 without having any exchange of information with the processor 2, and the corresponding part of an incoming subscriber is read. Then a busy tone is connected to the line 7 or the calling subscriber if the desired subscriber is busy. When the subscriber is not busy, the processor 2 is connected to transmit the incoming. Therefore, no exchange of information is needed with the processor 2 storing the corresponding subscriber in case a congestion occurs to the traffic to the incoming subscriber. In addition, it is not required for the processor 2 to discriminate the subscriber state, etc. Thus congestion can be prevented. |
