Patent ID: 7769369

Claim:
A mobile terminal for receiving a phone number maintaining service capable of allowing a user to continue to use a previously assigned phone number regardless of a change in service provider, the terminal comprising: a memory for storing NAM (Number Assignment Module) information for receiving the phone number maintaining service; wherein the NAM information includes a service provider change identification number, a service provider identification number and a mobile identification number, for receiving a mobile communication service; the service provider change identification number is updated in the memory each time a service provider to which the mobile terminal has subscribed is changed; a key input module having a plurality of keys, for generating a call request signal input by the user; an RF (Radio Frequency) module for transmitting and receiving a call request signal including called terminal information and calling terminal information; a display for displaying a phone number of a calling terminal, determined from the received calling terminal information; and a controller for transmitting the call request signal to a called terminal through the RF module, and upon receiving a call request signal through the RF module, determining a phone number of the calling terminal from the calling terminal information included in the received call request signal; wherein the controller determines the service provider change identification number from the calling terminal information, determines a changed service provider identification number based on the detected service provider change identification number, and determines a phone number of the calling terminal by combining the changed service provider identification number with the mobile identification number included in the calling terminal information; and the service provider change identification number has two digits, a first digit indicates addition or subtraction on the service provider identification number and a second digit indicates a weight for performing addition or subtraction on the service provider identification number.