Features: 1.1 compatible with GPRS900/1800 standard 1.2 support to connect wireless internet in mobile environment. 1.3 support Chinese/English short message 1.4 short message group/ individual sending 1.5 mini external removable antenna,360 rotation, super strong signal receiving 1.6 support Window ME, 2000, XP, Vista, provide drive for windows, good compatibility 1.7 provide internet applications software for short message, convenient for the vendor to sell the card attached the software or not 1.8 instant plug and play, easy to handle, no need to restart the computer 1.9 stainless steel shell, elegant and durable. Specification: 2.1 standard USB/PCMCIA/Express Card54 interface 2.2 compatible with standard of unit and card separate 2.3 transmit rate:230.4Kbps 2.4 receiving channel:receive sensitivity<-104dBm(FER≤1%)； 2.5 maximum RF output power: 23dBm~30dBm 2.6 minimum RF output power: <-50dBm 2.7 power supply:3.0V~3.6V 2.8 operation current: 5 mA(standby); 10mA (resting); 350mA(transferring date)