DEVICE AND METHOD FOR CALLING CELLULAR PHONE USING PUBLIC SWITCHED TELEPHONE NETWORK IN MOBILE COMMUNICATION SYSTEM

摘要

PURPOSE: A cellular phone call apparatus and method using a PSTN(Public Switched Telephone Network) in a mobile communication system is provided to save a mobile communication use charge by using a wired/wireless network through a cellular phone. CONSTITUTION: If a user inputs a call conversion service request instruction through an input unit(S1), the call conversion service request instruction is inserted into a setup message and is transmitted to an MSC(Mobile Switching Center) for registering a call conversion service to a wired telephone(S2). A cellular phone receives a result value to the call conversion service registration to the wired telephone from the MSC, and judges whether the call conversion service registration is successful(S3). If the call conversion service registration is successful, the cellular phone outputs a successful sound to the user and performs an origination/termination call through a PSTN using the first UIM(User Interface Module) connected to the cellular phone and the second UIM connected to a corresponding wired telephone(S4). If the user inputs a call conversion service cancel instruction through the key input unit, the cellular phone attempts a call conversion service cancel operation to the MSC(S6). The cellular phone receives a result value to the call conversion service cancel to the corresponding wired telephone from the MSC, and judges whether the call conversion service cancel to the corresponding wired telephone is successful(S7). If the call conversion service cancel to the corresponding wired telephone is successful, the cellular phone outputs a successful sound to the user and performs a telephone conversation through the wireless network(S8).