Mobile communications system, call control server, and call control method supporting call transmission between a packet switched and a circuit switched network having different telephone numbers

摘要

A mobile communications system has a subscriber database, located in a second mobile communications network, which manages subscriber information of a mobile terminal and registers location information in response to a location registration request made by the mobile terminal to the second mobile communications network, and registers location information in response to a location registration request made by the mobile terminal to a first mobile communications network, and a call control server which changes a caller number in a call request to a telephone number assigned for the second mobile communications network and transmits the call request to a connection destination upon receiving the call request from the mobile terminal which is located under the first mobile communications network.