... balance notice, etc.. TM100 GSM Data Transmission Unit (DTU), GSM SMS Modem Brief Descriptions:TM100 DTU is a wireless Data Transmission Unit (DTU) ... electricity and gas fee, balance notice, etc.With standard RS232 or USB (optional) interface, easy connection with PC;Embedded TCP/IP ... InterfaceRS232: serial data rate of 1,200~115,200bits/s;USB: USB2.0;Support full AT commands;l Other InterfacesAudio: ...