I.IoT DTU (Data Terminal Unit)

A DTU is a wireless communication device responsible for converting serial port data (such as RS232/RS485) into IP data and transmitting it to a remote server (center) via wireless networks such as 4G/5G/NB-IoT. It is commonly used in industrial telemetry, remote monitoring, and other fields.

Core Function: Transparent Transmission. That is, it sends serial port data from downstream devices (such as PLCs, sensors, and meters) to the server unchanged, and vice versa.

How to Use (Standard Procedure): Using a DTU typically involves four steps. The following diagram clearly illustrates the complete process from hardware connection to data viewing:

Key Steps Explained:

1. Configuration Parameters

This is the most crucial step. You need to connect the DTU's configuration port to your computer via a serial port (USB to serial cable) and use the manufacturer-provided configuration software (such as USR-G, Yourenlian, etc.) or AT command set to configure it. Key configuration items include:

Network Parameters: APN (usually no changes required, or consult your ISP), network registration method.

Center Parameters (Most Important): Server IP address/domain name, server port number.

Serial Port Parameters: Baud rate, data bits, stop bits, parity bits (must match your downstream device).

Protocols and Functions: Select the transmission protocol (such as TCP/UDP/MQTT, etc.), whether to enable heartbeat packets, registration packets, data encryption, etc.

2. Data Center (Server Side)

The DTU is the client and requires a server program to receive data. You need to:

Write a Socket service program (using languages ​​such as Python, Java, C#, etc.) on a server with a public IP address to listen on the port configured on the DTU.

Alternatively, use the manufacturer's cloud platform (such as China Mobile OneNET, Alibaba Cloud IoT, or the manufacturer's self-developed platform), create products and devices on the platform, obtain the server address and port, and then allow the DTU to connect. This method eliminates the hassle of building your own server.

3. Data Interaction

Issuing Commands: The server can send data to the connected DTU, and the data will be output verbatim to the downstream device through the DTU's serial port.

Receiving Data: The downstream device sends data through the serial port, and the DTU will package it and send it to the server.

Common Problem Troubleshooting:

Unable to Connect: Check the SIM card, signal strength, APN settings, server address/port, and whether the server firewall has open ports.

Data Unreceived: Check whether the server program is running normally and whether the serial port parameters (baud rate, etc.) of the DTU and the downstream device match.

Frequent Disconnections: Adjust the heartbeat interval and check the network signal stability.