Patent ID: 7266129

Claim:
A communication line control method comprising: providing a plurality of communication terminal devices each incorporating communication functions containing voice communications and data communications, accommodating a plurality of communication lines connected to a network, and capable of controlling an arbitrary call; causing, if said plurality of communication terminal devices forming a plurality of groups and when a control request with respect to a specified call is made on an arbitrary communication terminal device within one group or when a state of the call changes, a line control unit of said arbitrary communication terminal device to give broadcasting notifications of a change in control reservation state with respect to the specified call to said line control units of said plurality of communication terminal devices within other groups; causing said line control unit of said arbitrary communication terminal device, after receiving acknowledgements about the control reservation state from said line control units, having received the broadcasting notifications, of said communication terminal devices within other groups, to give a right of control of the call to a distributed control module of said arbitrary communication terminal device that utilizes the communication lines; and causing said distributed control module of said arbitrary communication terminal device to execute exclusive control between said communication terminal devices within other groups by unifying the states about the specified call between said communication terminal devices of other groups without being aware of the communication lines.