Mobile cellular radio system

(57) When a summary user cannot use his cellular phone, For example, when having got into the airplane (2) by which the satellite telephone system (20) was provided, in order to enable it to convert the call to a user's cellular phone to a satellite telephone handset (25), An interface (52) is established between a satellite telephone system (4) and a cellular phone system (5). A user inserts in the suitable reading equipment of a satellite telephone (20) a card (card which suits its own SIM or existing satellite telephone equipment of a mobile phone), and, thereby, the card collation system (42) of a satellite ground station is connected to a host cellular network (50). This host cellular network has an interface unit (520) for which the operation of the usual base station is emulated, therefore although the move user's terminal is carrying out roaming of the host network, host cellular system (50), It works as if it was the present "busy. "Moreover, an interface (52) resets a user's existing call turn command, and when host cellular system (5) receives a busy tone from a base station emulator (52), it carries out routing of the call to the directory number of a terminal (20). In order that a host network can search recognition (IMSI) of a user handset, The data relevant to the user who has an identification code (directory number) of the 1st form is used, As the identification code of the 1st form relates to the identification code (IMSI) of the 2nd form, it accesses a register, The above-mentioned signal is answered, the code of the 2nd form is received from a register, and the method of transmitting a position update condition to a related switching system to the identification code of the 2nd form of the above is used.