The origin of DTU

DTU was composed of modulator and demodulator at begining, its transmission form is to transmit encoded digital information. The transmission was performed within the frequency range of standard telephone lines at that time, transmitted to another DTU over telephone channel and decoded on the received DTU.

As early as 1920s, there were DTUs. In 1940s, DTU was used in typewriters, transmission speed of DTU was 25 bytes/second at that time. By 1958, DTU was used in military and was called smart DTU.

With continuous development of science and technology, 3G, 4G and Nb IoT appeared, 4G DTU and Nb IoT DTU appeared accordingly. Subsequently, due to maturity of short range communication technologies such as Lora, WiFi and Bluetooth, Lora DTU, WiFi DTU and Bluetooth modules appeared one after another also.

Basic functions of DTU

No matter what functions DTU has, it is inseparable these four basic functions, these four functions are the most basic and necessary.

1.Internally integrated TCP/IP protocol stack

There are external protocol stacks and built-in protocol stacks, most of them are external protocol stacks in the market. TCP/IP protocol stack can be considered as combination of wireless modem and embedded PC, DTU can realize dial-up Internet access and TCP/IP data communication.

2.Bidirectional conversion of serial port data

DTU can convert RS232, RS485, RS422 and other common serial ports data to TCP/IP data, since it is two-way transparent transmission, DTU can convert TCP/IP data to universal serial port data in return.

3.Support custom heartbeat package

One advantage of GPRS communication network is support permanent online function of the terminal device, so a typical DTU is designed to support permanent online function, this requires DTU to dial automatically and heartbeat data packets at startup to make it permanently online (when there is no data for long time).

4.Parameter configuration and permanent storage

The IP address, port number, and serial baud rate of data center are different in different applications, this enables DTU terminal equipment support parameter configuration function. The configured parameters can be permanently saved mainly in internal permanent storage devices, such as ordinary flash memory or EEPROM, once user start it, DTU will work according to the preset parameters automatically.