1.gsm modem, rs485 modem 2.with standard TCP/IP ... data transfer 4. Support DDNS IP modem, RS232 modem, GSM IP modem, GPRS data modem, data terminal,GPRS DTU, ... IP modem, Support transparent data transfe, gprs ip modem, gsm modemgprs modem with rs232 rs485 io for m2m meter readinggprs ... BandEGSM900/GSM1800MHz, GSM850/900/1800/1900MHz(optional)Compliant to GSM phase 2/2+GPRS class 10, class 12(optional ...