What is Data Transfer Unit?

A data Transfer unit is a wireless terminal device specially used to convert serial port data into IP data (or convert IP data into serial port data), and then transmit it through the wireless communication network. DTU has been widely used in electric power, environmental protection, LED information release, logistics, hydrology, meteorology, and other industries. Although the applied industries are different, the applied principles are the same. Most of the DTUs are connected to industrial equipment, such as PLC, single-chip microcomputers,s and other automation products, and then establish a wireless communication connection with the background. With the increasing development of the Internet today, the use of DTU is becoming more and more extensive. It provides assistance for information and industrial integration of various industries and between industries.

What is the connection between DTU and SOCKET?

DTU is a SOCKET client, and the data processing center is a SOCKET server. There are TCP protocol and UDP protocol for SOCKET connection, and the DTU and the center should use the same protocol, which is generally configured by the configuration software. After configuring the IP address and port number of the center for the DTU, connect the DTU to the user's equipment through the serial port.

DTU is connected with hydrology, electricity, meteorology, environmental protection, and other equipment and placed on site. After the DTU is powered on, it first registers to the mobile network, and then sends a SOCKET request packet to the mobile, and the mobile sends this request to the Internet.

After receiving the request, the server software of the center establishes a connection and sends a response message. The requested information sent by DTU is a data packet on the Internet. There are some reasons that will prevent the center from receiving the connection request packet so that the connection cannot be established.

The most common computer has anti-virus software, firewall, etc. to shield these data packets. The other is that the central computer accesses the Internet through a router, and data forwarding must be set on the router. Put a SIM card with the GPRS function in the DTU. After the DTU is powered on, it first registers to the GPRS network, and then establishes a connection with the data processing center through the GPRS network. In essence, the DTU and the data processing center establish a SOCKET connection. After the SOCKET connection is established, two-way communication is possible.

Internally integrated TCP/IP protocol

GPRS DTU internally encapsulates the PPP dial-up protocol and TCP/IP protocol and has an embedded operating system. From the hardware, it can be regarded as a combination of embedded PC and wireless GPRS MODEM; it has GPRS dial-up Internet access and TCP/IP data communication function.

Provide serial port data two-way conversion function

GPRS DTU provides a serial communication interface, including RS232, RS485, and RS422, which are commonly used serial communication methods, and most of the GPRS DTU designs the serial port data as a "transparent conversion" method, that is to say, GPRS DTU can convert the original data on the serial port into TCP/IP data packets for transmission without changing the original data communication content. Therefore, GPRS DTU can be connected with various user equipment using serial port communication, and there is no need to modify the user equipment.

Support automatic heartbeat, keep online forever

One of the advantages of the GPRS communication network is to support GPRS terminal equipment to be permanently online, so typical GPRS DTUs are designed to support the permanent online function, which requires the DTU to include automatic dialing when powered on and use heartbeat packets to maintain permanent online (when a long time there is no data communication, the mobile gateway will disconnect the connection between the DTU and the center, the heartbeat packet is a small data packet sent by the DTU and the data center before the connection is disconnected, so as to keep the connection from being disconnected), support disconnection automatic reconnection, automatic redial and other features.

Support parameter configuration, permanent storage

As a communication device, GPRS DTU has a wide range of applications. In different applications, the IP address and port number of the data center, and the baud rate of the serial port are all different. Therefore, GPRS DTU should support parameter configuration and save the configured parameters in the internal permanent storage device (usually FLASH or EEPROM, etc.). Once powered on, it will automatically work according to the set parameters.

Support user serial port parameter setting

The serial port parameters of different user equipment are different. When the DTU is connected to the serial port of the user equipment, the DTU terminal should be set according to the actual parameters of the user equipment serial port to ensure normal communication and reliable data transmission of the user equipment.

The more professional GPRS DTU also provides some extended functions, mainly including support for data center domain name resolution, support for remote parameter configuration, remote firmware upgrade, support for remote SMS/telephone wake-up, support for local serial port firmware upgrade, provide SMS channel, provide DTU online, offline level indication, etc.

Most of the DTUs are connected with field equipment, such as the connection of automation equipment such as 3-axis PLC  and single-chip microcomputer and the communication connection of wireless network is established with the cloud platform. With the continuous and rapid development of the Internet, the application of DTU has become more and more extensive. It helps the integration of data information and industries in various industries and between industries. It has also gradually developed into a key core technology of the Internet of Things.

More advanced DTUs can also provide users with secondary development functions, for example, communication plug-ins, DLLs, and interface documents, so that users can modify DTUs according to their actual conditions, improve DTU products, and make them more suitable for their own needs.

The main function of the DTU is to transmit the data of the remote device back to the background center wirelessly. To complete the data transmission, a complete data transmission system needs to be established. This system includes DTU, client equipment, mobile network, and background center. At the front end, DTU and the customer's equipment are connected through the 232 or 485 interface. After the DTU runs, it first registers to the mobile GPRS network, and then establishes a SOCKET connection with the background center set in the DTU.

The background center is the server of SOCKET, and DTU is the client of the SOCKET connection. 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 background center can conduct wireless data transmission through DTU, and it is a two-way transmission.

Full coverage of the three major operators' networks (full Netcom, supporting 2G/3G/4G at the same time). The high-speed wireless transmission is smoother, and it is compatible with dual SIM cards, making users more choices and more simple and convenient.

Wide coverage, strong signal

Proprietary impedance matching circuit design and excellent high-quality high-gain antenna make the signal of DTU equipment stronger, powerful receiving ability, and signal search with more sensitive response speed. Strong wall penetration performance and ultra-wide signal coverage performance.

The compatibility of various protocols and interfaces makes the project application more convenient and efficient.

Support RS232, RS485, and RS422 multiple interface options, compatible with all serial port lower computers.

Dropped and reconnected, high stability

The software and hardware are equipped with watchdog technology, and multiple protection devices, and have the characteristics of automatic reconnection and automatic redial when the device is disconnected. It adopts the TCP heartbeat link detection mechanism, disconnected reconnection, and data cache reissue, and the transmission is stable packet loss.