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This is an industrial grade 4G DTU which incorporates Qualcomm platform 4G communication module SIM7600E-H. It supports multi mode multi band, and suits multi countries or regions. After our secondary development for the module firmware, it takes only some simple configurations to achieve bidirectional data transparent transmission between RS232/RS485/TTL serial port and 4G LTE network.

With features like four modes support (TCP/UDP, Modbus, HTTP, and MQTT), RNDIS dial-up, and GNSS positioning, this industrial grade DTU is designed to be fully functional, easy to use, and stable operating. It would be an ideal choice for fields including industrial data collection, communication, remote control, and other IoT applications that need high throughput 4G data communication and have high requirements of data rate and latency.


  • Based on Qualcomm platform 4G communication module.
  • Features RS232, RS485, and TTL port (3.3V/5V).
  • USB Port, supports USB dial-up, configuration, AT command, and so on.
  • Supports high-speed UART interface, up to 921600bps.
  • Support TCP, UDP, HTTP(S), MQTT protocol, 4 channel socket connection.
  • Support Modbus protocol.
  • Support Domain name connection, automatically re-connect.
  • Support Registration Packet, the packet is modifiable, HEX format.
  • Support Heartbeat packet, the packet is modifiable, HEX format.
  • Hardware watchdog to avoid a crash.
  • The fault restart time is configurable.
  • The trigger time and triangle length of UART are configurable.
  • Industrial design, with EMC.
  • Working temperature: -40°C ~ 80°C.
  • Easy to use.


Product Type





LTE-TDD: B38/B39/B40/B41


LTE-TDD: B1/B3/B5/B7/B8/B20

LTE-FDD: B38/B40/B41





GSM/GPRS/EDGE: 900/1800MHz

Available Areas

Chines, Southeast Asia

Europe, Middle East, Africa, Korea.


Data Rate

4G (LTE Cat-4)

150Mbps(DL) / 50Mbps(UL)

3G (HSPA+)

42Mbps(DL) / 5.76Mbps(UL)


236.8Kbps(DL) / 236.8Kbps(UL)


85.6Kbps(DL) / 85.6Kbps(UL)


Software Function

Communication Protocol


Socket Connection

Support configuration 4 channel socket

Modbus acquire

Support auto-sample by Modbus with 5 sets of command, Users can configure the command interval.

Heartbeat Packet

Users can configure the Heartbeat packet, define the time interval. HEX format

Registration Packet

Users can configure the registration packet and the IMSI packet.

Software Protection

Support automatically reconnects, and the fault restart time is configurable.

Configure Parameters

Upper computer/Cloud/SMS


Hardware Description

UART interface


  • Connector:DR9 female
  • Protection:TVS protection, anti-surge, ESD protection


  • connector: screw terminals (A, B)
  • protection: 600W lightning-proof, anti-surge, and 15KV ESD protection (reserved 120R balancing resistor solder pads)


  • operating voltage: 3.3V or 5V
  • connector: screw terminals (TXD, RXD, GND)

Serial port baud rate

supports 300bps ~ 921600bps, 115200bps by default

USB port

  • operating voltage: 5V
  • connector: Micro USBB
  • protection: ESD protection diode
  • usage: parameter configuration, dial-up, firmware upgrade

Power input

  • connector: 7~36V screw terminals or DC 12V jack
  • protection: Schottky diode protection, reverse-proof

Hardware protection

embedded MCU, hardware watchdog to prevent system crash, industrial-grade aluminum alloy case

Operating voltage

7~36V DC

Operating current

idle: 10~30mA @12V

transmit: 80~450mA @12V (depending on the network condition)


PWR (power supply), RXD/TXD (UART RX/TX), NET (network), LINK (socket connection)


reset button

SIM card

standard SIM card (1.8V / 3V)

Antenna connector


Operating temperature


  • not available for the moment, contact us if you're interested

Software Description

Application Diagram

SIM7600E-H 4G DTU Spec.jpg

  • In the figure above, after the DTU is set to the corresponding working mode, the serial device can directly transparently transmit "data" to the "TCP/UDP/HTTP/MQTT cloud server" through the serial port.

Working Modes

It supports transparent transmission through the serial port, and four working modes can be set.
TCP/UDP transparent transmission mode
It can realize two-way data transparent transmission between serial device and network server, support setting 1~4 socket connections, and support heartbeat packets and registration packets.
SIM7600E-H 4G DTU Spec01.jpg
Modbus Mode
Support Modbus to automatically collect sensor data at regular intervals, and 5 Modbus collection commands can be set. After the user sets the command, DTU will periodically read the sensor data and send the read data to the server.
SIM7600E-H 4G DTU Spec02.jpg
HTTP(S) Mode
Supports customizing the HTTP/HTTPS server address and port for receiving data. After the host computer sets the parameters, DTU will POST the serial port data to the corresponding server.
SIM7600E-H 4G DTU Spec03.jpg
Support multi-topic subscription and multi-topic publishing
SIM7600E-H 4G DTU Spec04.jpg




Indicators and Buttons


  • PWR:lights up red when power-on
  • TXD:blinking blue when transmitting data
  • RXD:blinking blue when receiving data
  • NET:blinking green when network connection is established
  • LINK:lights up green when connects to a socket server
  • RESET:reset button


Hardware required

To test the device, you should prepare components.:
Package includes :

SIM7600CE-H 4G DTU × 1
GPS Antenna × 1
4G Antenna × 1
1.5m male to femal cable × 1
USB type A to micro cable × 1
12V Power adapter × 1
SIM7600X 4G DTU Package

External devices required:

Compute × 1
USB TO RS232/485/TTL × 1
4G SIM card(4G network should be available) × 1

Hardware Connection

In order to directly connect the PC for testing, it is recommended to purchase: USB TO RS232/485/TTL.

About the hardware connection of the DTU test, you can refer to the picture below.

Hardware connection

DTU Start and Reboot

Start: The NET indicator light on or blink after powering
Reboot: The device reboots if you press the RESET button.

Software Environment

Hereafter we use Windows 10 as an example, show you how to test the 4G DTU.

Install Driver

You need to install the driver when you first time use the 4G DTU. Drive of SIM7600X 4G DTU:

  • Connect the USB interface of the 4G DTU to Windows PC.
  • Open the Device Manage -> Other Devices —>"SimTech, Incorporated" —> Update Driver —> Browser Compute to find the driver —> Choose the driver —> Install.
  • Update drivers for all the devices.



Supports RNDIS Dial-Up via the USB port on Windows/Linux(including Raspberry Pi).


The DTU can support 150Mbps Downlink Speed And 50Mbps Uplink Speed Ideally. But the actual speed is affected by factors such as network coverage, network congestion, and base station conditions.

RNDIS Dial-Up on Windows 10

  • Connect the SIM card and antenna to DTU, and connect the USB interface of the DTU to the computer, power on the DTU.
  • Install the USB driver(refer to #Install Driver)
  • Open SSCOM and find out the serial port number corresponding to the AT serial port you are using. Then send the following command to query whether the device is registered on the network:
  • If the device has successfully registered on the network, then send the AT command to enable USB dial-up to the Internet:
  • If the transmission is successful, the DTU will return OK and reboot automatically.
  • And then you can find that there are some unrecognized devices in the Device Manager on the computer, such as RNDIS (with an exclamation mark).

RNDIS Dial-up01.png

  • Right-click the 'RNDIS', search "Update Divers" and select "Let me pick from a list of available drivers on my computer", then select "Network adapters" from the device list.

RNDIS Dial-up02.png

RNDIS Dial-up03.png

  • Select "Microsoft" in the manufacturer list of the Network adapters window, and then select "Remote NDIS Compatible Device" in the list on the right, which is the remote NDIS compatible device.


Click 'Next' and wait for the installation to finish, the RNDIS Kitl device will be installed successfully. And then you can see that the PC can access the Internet via DTU.

RNDIS Dial-Up on Raspberry Pi

Please refer to Raspberry Pi networked via RNDIS

Disable DTU dial-up Internet access

Open the corresponding AT serial port and send the AT command to close the USB dial-up Internet access:


The DTU will restart automatically, and the dial-up Internet access function will be turned off after restarting.

AT command Description

The DTU can support Serial command configuration, USB command configuration, PC upper computer configuration, and Cloud remote configuration.

Serial command configuration

After the DTU is turned on successfully, the serial port will output RDY. After that, you can receive, set, and query commands through the serial port within 10 seconds.

  • Query the current configuration parameters: AT+DTUCFG?
  • Use the following command to configure the parameters

The command format is as follows:


【Note】Parameter description:

BandBpr: Serial port Baud rate
Ip: Server address, support domain name
Port: Port number
EnRegister: (1/0) enable and disable registration packet
RegisterStr: registration packet
BeatPeriod: the interval of heartbeat packet, the unit is second
Beat: The content of heartbeat packet
UrcEn: URC enable bit, the serial port connected to the server will report "CONNECT SERVER OK"
SleepEn: Sleep enable, 1 is enable
CtrlEn: Flow control enable, 1 is enable
ReadTimeout: Regular 500MS report data to the service area, the value range is 100 to 500
Maxlen: 0 means that any data received by the serial port will be sent immediately, and the sending will be triggered when the length is long enough. The value range is 0-1460.
ServerCmd: 1, Indicates that the server can send AT+DTUCFG command to query and set the current DTU parameters, and can send AT+CRESET to remotely restart DTU
MaxLink: the number of multiple connections, if 0 means single link, the parameter value range [0, 2, 3, 4]
ModeBus: 1 means to enable MODBUS, 0 hexadecimal, after enabling, you can set up to 5 groups of commands to actively read the slave
RebootPeriod: Restart time in case of failure, the unit is 5S, such as setting 60 minutes(3600 seconds), the parameter is 3600/5=720, this fault means to the failure to connect to the server.
  • The command to set APN individually: AT+APN=apn
  • The command to set server address individually: AT+HOST=IP,Port

USB command configuration

Connect the USB of the DTU to the PC and install the driver, find the corresponding AT serial ports for the serial ports you are listing on the PC, and then you can use the PC serial port tool to query or configure the current parameters.

Here we give an example:

  • Open serial port tools, such as SSCOM, set the baud rate to 115200, press ‘Enter’ at the end of the current command to wrap.
  • After DTU is turned on, find the corresponding AT serial port and send the command as below:

Set the first link:


It will return OK after setting successfully, and the parameters need to be set according to the actual situation.

Set the second link:


It will return OK after setting successfully.

Set the third link:


It will return OK after setting successfully.

And then reboot the DTU, then you can see the LINK light turn on if the first parameter is connected to the Server.

PC master computer configuration

Connect the USB interface of the DTU to the PC and install the driver, and then download the configuration tool DTU Manager (EN)

DTU Manager

  • Click the "Scan Port" button at the bottom left of the DTU Manager, and you can see 'Equipment ready' in the right display window.
  • After filling in the configuration parameters manually, click the "Download" button to update the configured parameters to the DTU device and restart it to take effect.
  • Also, you can read the currently configured parameters of the DTU by press 'Get' button.

For operation demonstration, please refer to the 'Quick Start' section above.

Cloud remote configuration

To use this function, you need to enable the cloud configuration through the other parameter configuration methods above in advance. After enabling, the operation is the same as "Serial Command Configuration".

The reference video

TCP Server Configuration

You should set up the TCP server to test TCP/UDP communication.
If you have a cloud server, you can run the SocketTest in your Cloud server. You just need to configure the software and enable the port:


Note: If you do not have a TCP server, you can also use a free TCP server(IP: ;Port:2317 ;) for testing, the configuration is the same as above.

Host PC Configure STU

Connect hardware, and run the configure software in the host PC. Configure the DTU as below:

Setting Parameter
Working mod TCP/UDP Mode
Baud rate 115200
Protocol TCP
Start server 1
Port 2318

Click "Download configuration" and then "Restart DTU" after setting.

DTU Setting

Serial port Transparent Transmission test

Refer to the "Hardware Connection" above to connect the hardware. You can choose any one of UART, RS232, or RS485 of the USB TO RS232/485/TTL to connect to the corresponding interface of the DTU. As well as to set up the switch of the "Communication Interface Setting" according to the interface you are using.


Working mode

TCP/UDP date Transparent Transmission

Support bidirectional data transparent transmission between RS232/RS485/TTL serial devices and 4G/3G/2G network server. Configurable 1-4 channel socket connections, supports heartbeat packet and registration packet.

TCP/UDP date Transparent Transmission

Please refer to the 'Quick Start' section to test the function of TCP/UDP date Transparent Transmission.

【Note】: The effective length of a frame of data in the TCP protocol is 1460 bytes, the header and the end of the date total 40 bytes, so the maximum length of a frame of data is 1500 bytes. Therefore, the serial port transmits and receive buffers of the SIM7600X 4G DTU are both 1500 bytes.

The reference video

Software preparation

Three modes description

AT+DTUMODE=0 DTU function by default
AT+DTUMODE=1 Restart http function after setting
AT+DTUMODE=2 Restart mqtt function after setting

HTTP communication

  • Use the following command to set up the http function
  • According to the table below, configure DTU parameters -> download parameters -> restart DTU
Baud rate 115200
Conmmunication protocol HTTP(S)
Server address

SIM7600E-H 4G DTU (1).png

Upload data to the web

  • Select any interface of UART, RS232 or RS485 to connect to the corresponding interface of DTU, send the following data in sscom, and return POST OK to indicate that the data is successfully uploaded.

{ "apikey": "tPmAT5Ab3j888", "value1": "33", "value2": "3", "value3": "22"}

SIM7600E-H 4G DTU HTTP (3).png

SIM7600E-H 4G DTU HTTP (2).png

Modbus automatically collects sensor data

The DTU will automatically and periodically collect sensor data and send it to the network server, which supports up to 5 commands.

Modbus Periodic Collection

Instructions for use

If you need to read multiple slave data at once, you need to set multiple instructions.

And you can set the time interval for each reading, such as 10s, 1 minute, one hour, etc. This time interval is called the command cycle. If there are multiple commands that need to be read each time, the time interval between each command is called the command interval.

  • For example

If you need to read the data of two sensors every half an hour, you can set the command cycle to 1800s and the command interval to 100ms.

SIM7600X 4G DYU Modbus.png

SIM7600 modbus (1).png

  • Configure TCP, set the baud rate to 9600, and fill in the IP address and port number of the server (this is the TCP server shared on the Internet).

SIM7600 modbus (2).png

  • Configure Modbus. After modbus is enabled, fill in the hex data to be fed to the RS485 serial port into CMD1-CMD5(note that there is no space in the data).

SIM7600 modbus (3).png

  • After the configuration is successful, SIM7600E - H 4 g DTU to Modbus RTU Relay sends data every 2.5 seconds, then returns data to DTU, DTU uploads data to server, and channel 1 switch of relay reverses every 2.5 seconds.

The reference video

Hardware preparation

  • SIM7600E-H 4G DTU × 1
  • USB TO RS232/485/TTL × 1
  • 4G SIM card(4G network should be available) × 1
  • PC

Software preparation

MQTT communication

  • 1. Configure DTU_Manager, fill in the corresponding parameters to DTU_Manager according to the following table->download parameters->restart DTU.
Domain name (server public network IP)
Port number 1883
Passward Customize or NC
Username Customize or NC
Customer ID Customize
SIM7600E-H 4G DTU (1).png

  • 2. After downloading the parameters to the SIM7600E-H 4G DTU, the LINK light is on, and the server has been successfully connected.
SIM7600E-H 4G DTU (2).png

  • 3. After configuring the MQTT tool mqttfx-1.7.1 according to the figure below, DTU connects to the same server.
SIM7600E-H DTU MQTT (6).png

  • 4. After successfully connecting to the server, send "topic: Tomorrow will be better!" to DTU via TTL, RS232 or RS485. After subscribing to the same topic on the MQTT tool, you can receive the message from DTU: "Tomorrow will be better!" "
SIM7600E-H 4G DTU (3).png

  • 5. After subscribing to the same topic, the MQTT tool can receive the message from DTU through the MQTT tool: "Yesterday is the past!, and then the port of the TTL, RS232, or RS485 will receive the message: "Yesterday is the past" !"
SIM7600E-H 4G DTU (4).png



The RNDIS mode COM port can be loaded with the following drivers:
SIM7600X Driver

Due to the instability of GPS indoor satellite search, please place the module or antenna next to the balcony or window, or experiment directly outdoors. Plug in the GPS antenna, and place the receiver label face down in an open space. Under normal conditions (outdoor, good weather, no large buildings), it will take about 1 minute to receive the positioning signal; if the weather condition is bad, it may take longer to locate, or even impossible to locate.



Reboot the SIM7600E-H after sending the following command:




Technical Support

If you need technical support or have any feedback/review, please click the Submit Now button to submit a ticket, Our support team will check and reply to you within 1 to 2 working days. Please be patient as we make every effort to help you to resolve the issue.
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