| 摘要 |
<p>Call processing method on PABX (Private Automatic Branch Exchange) is capable of decreasing call loss probalitity upon line bush due to the trunk line limit. Waiting queue stored in RAM is defined to store each call without corresponding call loss and then to connect with the trunk line depending upon queuing. The call processing and its necessary data are stored in the EPROM or RAM and are controlled by the CPU. The waiting queue is calculated by the latticels formula L=λW whereλis average call arrival time, W is average waiting time, L is queue length. The processing routine mainly consists of stages, decision on busy line/not (3b) storing the call on busy (3c,3f), sending the outgoing call to subscriber till time-out (3g,3h,3k) and sending busy time (3i,3l) upon processing coder.</p> |
