... Optional GPRS modem 3G modem M2M GPRS Modem With RS232 RS485 for Meter Reading Temperature and Humidity Monitoring ( ... stack, supports transparent data transmission, AT Command, RS232/485, remote configuration and control, with embedded Operation System, such as LINUX ... . It has been used for data communication/acquisition, remote control and minotring, M2M appliation, etc. Detailed information A. ...