摘要 |
A private branch exchange system facilitates the expansion of extension telephones and extension groups, and can quickly transfer an overflow call from extension telephones supported by one private branch exchange ("PBX") to an extension telephone supported by another PBX. The PBX system is formed such that a plurality of PBXs connected to telephone network and connecting a plurality of extension telephones are composed a PBX with communication line. Each PBX queues an incoming call arriving through telephone network in reception sequence queue common to the overall PBX network. Each PBX scans the distribution sequence queue common to the overall PBX network to select an optimal extension telephone. Additionally, each PBX connects the incoming call to the selected extension telephone when the selected extension telephone is accommodated by the one PBX in which the call is detected, and when the selected extension telephone is accommodated by another PBX, transfers the incoming call to the other PBX through the communication line. |