In a General Packet Radio Service (GPRS) Class B communications system, a mobile station includes a packet generating module for generating data packets to be transmitted wirelessly by the mobile station. The packet generating module is capable of receiving voice data and non-voice data, and is operable in a multi-content mode, in which the packet generating module encapsulates the voice data and the non-voice data to result in the data packets. In addition, a data transmission method for synchronous transmission of voice and non-voice data is to be implemented using a GPRS Class B communications system that includes a mobile station. The data transmission method includes configuring a packet generating module of the mobile station to encapsulate the voice data and the non-voice data to result in data packets that are to be wirelessly transmitted by the mobile station for subsequent reception by a network server.