... 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 ... , input pulse counter and pulse wave output function. Ideal for M2M fields, smart grid, industrial automation, telemetry, finance, POS, water supply, environment protection ...