Research On USB Interface GPRS Wireless Network Card

Wireless network is new technology having emerged in recent years, including WLAN and WWAN. With the development of technology and cost depression, surfing on the Internet by Wireless network is gradually popular. The different wireless network covers the different scope, provides the different network band width. Thereinto, GPRS network of China Mobile covers 31 provinces and more than 240 cities in the whole country at present; it covers the widest coverage area with optimum quality and high capacity at present in China.First, GPRS technology is analyzed in this paper, included the System structure of GPRS and the protocol of the transmission platform, and the characteristic of GPRS module is introduced. General Packet Radio Service (GPRS) is the new bear service which is developed from GSM network. GPRS networks provide packet-switched services based on IP protocol, which make End-user can access the external packet data network—Internet. A GPRS module consists of wireless communication module, audio module, display module, SIM card module and interface module. Choosing an appropriate interface not only affects data transmission speed between the computer and GPRS module, but also affects the portability and the compatibility of the device.Second, the structure and the principle of USB are analyzed in the paper. USB supports PnP (plug and play), has the high data transmission speed, can supply power for the USB device directly, so it dose not need power supply. USB already became the main interface which communication between the computer and the external device. The majority of GPRS module only supports the UART. It must use the transform chip to realize between USB and the UART transformation, and gives the support in the driver.Third, the structure and the principle of the WDM driver are analyzed in the paper, Special the programming interface of the USB driver; And studied the realization principle the driver of USB transfer to the serial port, elaborated the design method of the USB interface GPRS wireless network card.Finally, the USB interface GPRS wireless network card is tested by the application which is programmed by RAS (Remote Access Service) API. Summarized the position of the system which needs to improve, and provided the direction to further study.