... 4. Support DDNS IP modem, RS232 modem, GSM IP modem, GPRS data modem, data terminal,GPRS DTU, TCP/IP modem, Support transparent data ... transfe, gprs ip modem, gsm modemgprs modem ... with rs232 rs485 io for m2m meter readinggprs modem(DTU) with I/OF2114 ...