... and gas fee, balance notice, etc.. TM100 GSM Data Transmission Unit (DTU), GSM SMS Modem Brief Descriptions:TM100 DTU is a wireless Data ... Transmission Unit (DTU) based on GSM network, it uses ... SMS, DTMF;Data GPRS: GPRS Class 10, Coding:CS1-CS4, embedded TCP/IP Protocol;Data CSD: Transmissions rates 2.4, 4.8 ...