A mobile communication system is provided that employs a data communication control method that includes a radio control apparatus that communicates with a mobile station that performs VOX control using a first frequency band area and a second frequency band area. Receiving a request for data transmission to the mobile station, the radio control apparatus determines whether radio wave transmission and reception are being performed with the mobile station in a communication operation using the first frequency band area. The radio control apparatus then determines a transmission time for data transmission in a communication operation using the second frequency band area, based on a communication pattern of the mobile station that is a data transmission destination designated by the request for data transmission. If radio wave transmission and reception are not being performed in the communication operation using the first frequency band area, the radio control apparatus transmits the requested data to the data transmission destination mobile station within the determined transmission time.