-2000 Codec Control Method of a Mobile Station Providing Circuit Switched Service in the Asynchronous IMT-2000 System

摘要

PURPOSE: A method for controlling a CODEC of a mobile terminal for a circuit switched service in an asynchronous IMT-2000 system is provided to obtain a mobility management connection for an originating call, and to indicate CODEC function activation with a CODEC module, thereby securing voice and video calls. CONSTITUTION: A call control protocol waits until a call setup request is received(S301). If the call setup request is received(S302), the protocol obtains call setup targeted service information(S303) and obtains a mobility management connection for an originating call(S304). The protocol requests CODEC function activation of a CODEC module(S305), and starts a response standby timer for the CODEC function activation(S306). The protocol waits whether a CODEC function activation response is received from the CODEC module(S307). If not, and if the response standby timer expires(S311), the protocol performs a canceling procedure for the mobility management connection(S312), and sets a CODEC operation mode to 'Fail'(S313). The protocol informs a user that a call is not set, and completes the procedure(S314).