... and embedded with High reliable ARM7 CPU.Based on the public net, KB3030 SMS group sending GSM / GPRS MODEM transmit widely, stably ... atmosphere, ensure high quality for your device.Aim at different scope user’s requirements to supply different define GPRS Terminal unit, ... default), Modem, SMS Modem. DTU mode is GPRS data transmission which can get the data from device’s COM port (RS232/RS485/TTL) ...