Patent ID: 7586900

Claim:
An Internet protocol-private branch exchange having an instant messenger function, the Internet protocol-private branch exchange comprising: a private branch exchange unit for performing transmission/reception of voice and data among an office line telephone, an extension telephone, a computer and a wired/wireless Internet terminal after being connected to a public switched telephone network, an extension network and an Internet protocol network; a messenger server unit for transmitting/receiving an instant message, a file and an e-mail by using instant messenger software executed in the computer and/or the wired/wireless Internet terminal after being connected to the computer and the wired/wireless Internet terminal, and providing and managing at least one of the functions of providing information for current status, position or address book of connected users and notifying reception of the e-mail by executing the instant messenger software; and a central controller for providing an inter-working function between the PBX unit and the messenger server unit, and temporarily holding provision of an instant messenger service and controlling a voice communication service to be provided between communication terminals requiring voice communication when a voice communication service request signal is received through the instant messenger software while the instant messenger service is being provided through the messenger server unit.