PURPOSE: To improve the processing capability of a decentralized control processing packet exchange with a few memory capacities by decentralizing a call setting processing function and a packet protocol processing function to plural processors.

CONSTITUTION: A terminal device 301 connected to a packet protocol processing processor 401 through a line 100 is used as a calling terminal device and a terminal device 302 connected to a packet protocol processing processor 402 through a line 400 is used as an incoming terminal device. The packet protocol processing processor 401 receiving a call setting request packet from the calling terminal device 301 selects a call setting processing processor 501 among call setting processing processors 501∼503 and transmits a call setting request signal corresponding to the call setting packet. Thus, the processor 501 uses a calling and a called terminal address of the call setting request signal to recognize a call from the terminal device 301 to the terminal device 302, selects the packet protocol processing processor 402 accommodating the incoming terminal device 302 and transmits an incoming notice signal.