The main function of DTU is to transmit data from remote devices back to the background center via wired/wireless. Different data transmission modes of DTU include all-network-connected DTU, GPRS DTU, WIFI DTU, CAN DTU and 4G DTU. Today, we will have a look at the structure and work flow of DTU.

To complete the data transmission needs to establish a complete data transmission system. In this system includes: DTU, customer equipment, mobile network, background center. On the front end, DTU is connected to the customer's device via a RS232 or RS485 interface. Therefore, DTU alone cannot complete the wireless transmission of data, and it needs to be used together with background software. After establishing the connection, the front-end equipment and the back-end center can conduct wireless data transmission through DTU, and the transmission is two-way. The new generation of DTU has developed to varying degrees in terms of simple data collection, multimedia display and data processing.

GPRS DTU communication

GPRS DTU working process:
After GPRS DTU is powered on, it first reads the working parameters saved in internal FLASH (including GPRS dialing parameters, serial port baud rate, data center IP address, etc., which have been configured in advance).

GPRS DTU logs on to GSM network and then does the GPRS PPP dialing. Upon successful dialing, GPRS DTU receives an internal IP address (typically 10.x.x.x) randomly assigned by the mobile. That is, GPRS DTU is in a mobile Intranet, and its Intranet IP address is usually not fixed and changes with each dial. We can understand that GPRS DTU is a mobile internal LAN device, through the mobile gateway to achieve communication with the external Internet public network. This is similar to how a computer in a LAN accesses an external network through a gateway.

GPRS DTU initiatively initiates the communication connection with the data center and maintains the communication connection. Because GPRS DTU is in the mobile Intranet, and the IP address is not fixed. Therefore, only GPRS DTU can actively connect to the data center, and not the data center can actively connect to GPRS DTU. This requires the data center to have a fixed public network IP address or a fixed domain name. The public network IP address or fixed domain name of the data center is stored as a parameter in GPRS DTU, so that once GPRS DTU is powered up and successfully dialed, it can be actively connected to the data center.

Specifically, GPRS DTU initiates TCP or UDP communication requests to the data center through parameters such as the IP address of the data center (if the domain name of the data center is adopted, the IP address of the data center will be resolved through the domain name of the data center) and port number. Upon receiving the response from the center, GPRS DTU is deemed to have successfully shaken hands with the center, and then the communication connection is maintained. If the communication connection is interrupted, GPRS DTU will immediately shake hands with the center again.
Now that the TCP/UDP communication connection has been established, data two-way communication is possible.

GPRS DTU application

Wide application of DTU:
DTU has been widely used in electric power, environmental protection, LED information release, logistics, hydrology, meteorology and other industries. Although the application industry is different, but the principle of the application is the same. Most of them are connected with industrial equipment, such as PLC, SCM and other automation products, and then establish wireless communication connection with the background. Today, with the development of the Internet, DTU is more and more widely used. It provides help for the information and industrial integration among various industries. It has also gradually developed into the core technology of iot application.



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