How to communicate between DTU

How to communicate between DTU

The structure of DTU How to communicate between GPRS DTU

　　 The main function of DTU is to transmit data from remote devices back to the back-end center via wired/wireless methods. DTU data transmission methods are different. DTU has full Netcom DTU, GPRS DTU, WIFI DTU, CAN DTU, 4G DTU. Today we will take a look at the structure and work flow of DTU.

　　To complete the data transmission, a complete data transmission system needs to be established. In this system include: DTU, customer equipment, mobile network, back-end center. At the front end, the DTU and the customer's equipment are connected through the 232 or 485 interface. Therefore, only DTU cannot complete the wireless transmission of data, and it needs to be used with the cooperation of background software. After the connection is established, the front-end equipment and the back-end center can carry out wireless data transmission through DTU, and it is two-way transmission. The new generation of DTU has developed to varying degrees in terms of simple data collection, multimedia display, and data processing.

　　 GPRS DTU working process: 

　　 After GPRS DTU is powered on, first read the working parameters stored in the 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 the GSM network, and then performs GPRS PPP dialing. After dialing is successful, GPRS DTU will obtain an internal IP address randomly assigned by the mobile (usually 10.X.X.X). In other words, GPRS DTU is in the mobile intranet, and its intranet IP address is usually not fixed, and changes with each dial-up. We can understand that GPRS DTU is a mobile device in the internal LAN at this time, through the mobile gateway to realize the communication with the external Internet public network. This is similar to the way that computers in a local area network access external networks through a gateway. 

　　GPRS DTU actively initiates a communication connection with the data center and keeps the communication connection always present. Because GPRS DTU is in the mobile intranet, and the IP address is not fixed. Therefore, only the GPRS DTU can actively connect to the data center, and the data center cannot actively connect to the GPRS DTU. This requires the data center to have a fixed public IP address or a fixed domain name. The public IP address or fixed domain name of the data center is stored as a parameter in the GPRS DTU, so that once the GPRS DTU is successfully dialed up, it can actively connect to the data center.

　　 Specifically, GPRS DTU initiates a TCP or UDP communication request to the data center through the data center's IP address (if the center domain name is used, the center IP address is first resolved through the center domain name) and port number and other parameters. After getting the response from the center, the GPRS DTU considers that the handshake with the center is successful, and then keeps the communication connection in existence. If the communication connection is interrupted, the GPRS DTU will immediately re-handshake with the center.

　　 Since the TCP/UDP communication connection has been established, two-way data communication can be carried out.

　　 Wide application of DTU:

　　DTU has been widely used in power, environmental protection, LED information release, logistics, hydrology, meteorology and other industries. Although the applied industries are different, the principles of application are the same. Most of the DTUs are connected to industrial equipment, such as PLCs, microcontrollers and other automation products, and then establish a wireless communication connection with the background. Today, with the increasing development of the Internet, DTU is used more and more widely. It provides help for various industries and the integration of information and industries among various industries. It has gradually developed into the core technology of IoT applications.