Q24plus Freuqency: 850/900/1800/1900 mhz Function: bulk send SMS,MMS,data manage Support: GSM/GPRS Interface type: USB * 32x SIM card(big/small) slots , Wireless access to internet , Comply with GSM phase2 standard * Maximum transmitting speed 115KBps , Input voltage: 100 to 240V * Support dual band:900/1800 MHz or quad-band GSM: 850/900/1800/1900 MHz , Meet the ETSI GSM 2 + standards * Supported operating systems: --Windows 7 (Home, Premium, Pro, Ultimate, Enterprise) --Windows Vista (Home, Business, Ultimate, Enterprise) --Windows XP (Pro and Home) --Windows Server 2003 (original and R2) --Windows 2000 (Server and Pro)