Mobile radio communication apparatus and control method for controlling the apparatus

摘要

A mobile radio communication apparatus having a communication function adaptable to both an analog mode and a digital mode is controlled by a control unit, when it receives from a radio base station a message signal representing that the digital mode is provided. When the strength of the message signal in the analog mode received by a receiving unit from the radio base station is at a predetermined level or higher, a mode of communication services is shifted into the digital mode. When the strength is lower than the predetermined level, the standby status in the analog mode is maintained. Therefore, the mode of communication services is not alternated between the analog mode and the digital mode, with the result that both an outgoing call and an incoming call can be performed successfully even in an unstable service area where a transmitted signal cannot reach the radio base station.