Internet protocol compliant private branch electronic exchange and a method expanding the number of controlled terminal ports

An Internet Protocol compliant private branch electronic exchange which conducts switching control of terminals falling under its control, the terminals being connected to a Local Area Network (LAN), and sending and receiving Internet Protocol packets for a call through said LAN, comprising:

• a multimedia gateway controller, which is connected to said LAN and performs call-control-processing tasks for said switching control, includes:
• a call control data master table for storing call control data of all of said terminals falling under control of the exchange;
• and
• a plurality of protocol handlers which are installed on a system bus connected to said multimedia gateway controller and connected to said LAN, each of said protocol handlers includes:
• a call control data slave table for storing call control data of specified number of said terminals selected and transferred by said multimedia gateway controller, wherein the specified number is an upper limit of the number of terminals which can be controlled by each respective protocol handler,
• terminal supervisory means for performing terminal supervision which supervises proper performance of said terminals specified in said call control data slave table by periodically transmitting a packet for supervision after said call control data slave table has been created and after sessions to said terminals specified in said call control data slave table have been set up,
• call control protocol transfer means for sending and receiving said Internet Protocol packets of call control for said terminals specified in said call control data slave table,
• fault supervisory/processing means for executing fault event supervision, fault processing and retransmission of layer 1 through 3 while said call control protocol transfer means performing sending and receiving said Internet Protocol packets of call control for said terminals specified in said call control data slave table, and
• call control protocol conversion means for converting a protocol of said Internet Protocol packets for communication with said terminal into a call control protocol applied within said multimedia gateway controller for said multimedia gateway controller to perform the call-control-processing tasks and vice versa for call procedures between said multimedia gateway controller and said terminal,
• wherein said terminal supervisory means and said fault supervisory/processing means perform said terminal supervision and said fault event supervision, fault processing and retransmission of layer 1 through 3 in place of said multimedia gateway controller.