... fee, balance notice, etc.. New GSM modem for bulk sms sending TM100 Key words: GSM SMS Modem, GSM Modem, SMS Gateway Brief DescriptionsTM100 DTU is ... a wireless Data Transmission Unit (DTU) based on GSM network, it ... of Tri-frequency GSM900/1800/1900 MHz(or quad-frequency GSM 850/900/1800/1900MHz);Support SMS, DTMF;Data GPRS ...