... school notice, school report, notice for electricity and gas fee, balance notice, etc.With standard RS232 or USB (optional) interface, easy ... make convenient theremote, high-speed and transparent data transmission;With watchdog for hardware and software, guarantee the stability of unit ... .0;Support full AT commands;l Other InterfacesAudio: EAR with MIC and SPK two jacks;Antenna: Standard SMA female ...