... CPU and embedded real time operating system,with TCP/IP protocol; F2003 GSM DTU SPECIFICATION F2003 GSM DTU ... used on finance, water supply, environment protection, electric power system, post and weather fields. Wireless Specification EGSM900/GSM1800Compliant ... RS232/RS485 serial port, rates: 110~230400bits/s Indicator lights: “Power”, “ACT”, “Online” Antenna interface: standard SMA female interface, ...