DATA TRANSMISSION LINE ESTABLISHING SYSTEM BETWEEN MOBILE TELEPHONE TERMINALS

摘要

In a network system including a radio base station to be accommodated in a mobile telephone network through an IP network, the radio base station, when receiving a calling request from a calling terminal, specifies a called terminal of the calling request. If the called terminal can receive the calling request by using another radio base station different from the base station connected to the IP network, it is tried to establish a data communication line, in which the radio base station and the another radio base station are connected through the IP network not by way of the mobile telephone network, so as to exchange the communication data between the calling terminal and the called terminal.