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)