PBX COOPERATION SYSTEM, PBX COOPERATION METHOD, SUBSCRIBER REGISTRATION DEVICE, AND SUBSCRIBER REGISTRATION PROGRAM

摘要

A subscriber registration server (16) (registration server) notifies another registration server (16) paired with another PBX server (11) within an area in which an IP-PBX server (11) paired therewith is included that a phone terminal has been registered, and when the notification has been given from the other registration server (16) paired with the other PBX server (11) within the area, writes the registration of the phone terminal in a subscriber database of the registration server (16). When receiving a call connection request with a phone terminal not housed therein as an outgoing call destination, the PBX server (11) inquires of the registration server (16) paired therewith, and instructs another PBX server (11) in which the phone terminal specified as the outgoing call destination is housed to call the phone terminal as the outgoing call destination.