AG-702

The AG-702 is multipurpose Industrial IoT Gateway based on OpenWRT system. Open WRT support more than 6000 ready applications in our repository. AG-702 has opto-isolated RS485 and RS232, two digital inputs and one relay output. Support Modbus RTU and Modbus TCP/IP. Dual Ethernet, isolated interfaces wide power supply range up to 60V is perfect choice for industrial control systems.

Please read carefully before starting. Also read the product safety information.

General information

Download technical specification Technical Specification

Model selection

Different Gateway models are available depending on the periphery availability and type.

Model
 Cellular Network
 GNSS
 Internal memory
GPRS 3G
 LTE 4G
 5G
Flash 64MB
 NAND 512MB
AG-702-V48




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Hardware informations

The Gateway is made on one PCB, which is fitted to the aluminum housing. The housing is made of a thick, strong aluminum profile with two end plates also made from aluminum. The surface of the housing is finished by anodizing. 

At the bottom of the housing there are slots through which DIN rail clamp or any other clamp can be mounted by t-nuts.

Top view dimensions

AG-702-dimensions-top.png

Side view dimensions

AG-702-dimensions-2.png

Connectors

Top view connectors and indicators

AG-702-connectors-A.png

AG-702-connectors-B.png

Block diagram

For a better understanding of the operation of the gateway, refer to the block diagram. Non-essential components have been omitted. Developers who program peripherals such as GPIOs, serial etc. will find information about them in the sections dedicated to such peripherals.

AG-702-block-diagram.png

Power supply

The Gateway power supply range is 8-48V DC (version V48). You need to connect the gate according to the inscriptions at the main connector. The Gateway is protected against reverse power connection. If the polarity is reversed, the Gateway will not start. 

PoE

The Gateway can also be powered via PoE in the range of input power supply using unused pairs of wires in the LAN cable. Below is the pinout of the RJ45 socket.

Pin number
 Function
 Comment
1
 RX+ Data
2
 RX- Data
3
 TX+ Data
4
 DC+ Power supply positive
5
 DC+ Power supply positive
6
 TX- Data
7
 DC- Power supply negative
8
 DC- Power supply negative

LTE 4G modem

Generally, the Gateway supports all versions of Quectel MiniPCI express modems. However, you can use a third-party modem, as long as the signal outputs are compatible with those of the Quectel company. For use your LTE module, select model without LTE module installed. You also need to pay attention to the power supply to the LTE module should be 3.3V.

Mobile network signal strength is also displayed on 4 LED indicators.

MiniPCI express pinout

Below is the description of the PCI express pinout used in the AG-702. Before installing anything other than the EC200U or EG25, be sure to check the pinout for compatibility. The LTE model is connected via a USB data bus.

AG-702-PCIexp.png

GNSS

Device has wboded LTE modem along with GNSS function. In order to receive the GNSS signal, an antenna is required. There are two types of GNSS antennas: active gnss antenna and passive gnss antenna. The AG-702 supports both types of antennas, but in order for the active antenna to work properly, it is necessary to start powering the active antenna. To do this, you need to go to System > Custom Commands and select the command Turn GPS antenna to active mode.

Also on this page, you can test whether the GNSS is working properly.  To do so, you need to click Activate GPS on ttyUSB7 and then Show GPS location.

Ethernet

The gateway has two RJ45 ethernet ports with LED indicators. The speed of each is 100Mbps. By default, Ethernet-1 is configured as a WAN port and Ethernet-2 is configured as a LAN port. Ethernet-1 supports PoE on free RJ45 pairs.

The default IP of ethernet:
Eth-1: DHCP
Eth-2: 192.168.1.1 

WiFi

The gateway has WiFi 2.4Ghz. By default, the WiFi is set as a hotspot and shares internet from Ethernet and from LTE via WiFi.

WiFi is used for remote configuration of the device. It does not have a long range, so it may not fully meet some requirements.

RTC

The gateway has a built-in RTC with battery packup power. The battery used is CR1220 size. In "S" models there is superCAP backup.

All gateways that are exported due to transportation regulations are sold without batteries.

Serial Interface

The Gateway has two serial ports. One RS232 and one RS485. Both ports are optically isolated from the main computer circuit, but are not isolated from each other. In addition to insulation, they are also protected against surges.

RS232

The RS232 port includes CTS and RTS signals in addition to TX and RX signals. The baudrate range for the RS232 port is 300bps to 230400bps . The port is protected by high-power TVS diodes against electrical surges.

RS485

The baudrate range for RS485 port is 600 bps to 460800 bps. Note that with a longer cable, the maximum speed may drop. It is recommended to use special cables designed for RS485. The port is protected by high-power TVS diodes against electrical surges.

Digital I/O

The Gateway has two digital inputs and one digital output.

Digital inputs

The digital inputs are completely independent optically isolated inputs that accept an input signal level of up to 30V DC. They have no common minus. They can be connected either with a common plus or minus. Can be controlled with open collector. They require to be powered. The range of the signal considered as a logical 1 is from 3.5V to the maximum input voltage.

Digital output

The digital output is realized on a relay whose load capacity is 3A. The maximum voltage is 160V AC and 30DC. The output is only in normal open format (NO).

LED indicators

The AG-702 gateway has fourteen indicators on the front panel. By default, they are programmed to perform certain functions, but they are all controlled by the processor and knowing the OpenWRT system well, change their functions.

AG-702-LEDs.png


System Configuration Manual

Please read carefully before starting. Also read the product safety information.

1. First start

After unpacking, the gateway is ready to use, but requires configuration to adapt to the required functions. 

1.1 Power supply

First, connect the power supply according to the power supply information.

2. Opening inbuilt website

2.1 Through the WAN interface

To access the built-in website, connect the gateway by WAN to the local network and enter the DHCP assigned IP address in the address window of the browser. Please note that it may take some time from powering on to booting up the system. When the LEDs next to the RJ45 socket start flashing, after about 10 seconds the built-in website becomes available.

user name: root 
password: root

2.2 Through the LAN interface

Connect the ETH2 directly to the computer and enter in the address window of the browser default IP of Gateway.

IP: 192.168.1.1

user name: root 
password: root

2.3 Through the WiFi interface

By default, the gateway creates its own network with default ESSID "AG-702". The network is secured with default password "atreyo12".
Connect to this network and enter the IP in the address bar of your browser.

IP: 192.168.1.1 

user name: root 
password: root

AG-702-web-login.png

ASfter logging in, you are automatically taken to the dashboard page.

AG-702-web-overview.png

2.4 Password setting

At the top there is a message that no password has been set.

AG-702-web-overview-password.png

Set a password on the system>administration page:

AG-702-web-change-password.png

To maintain security, it is recommended to use long and complex passwords.

3. System statistics

The gateway has a built-in real-time statistics system under Status > Realtime Graphs and accurate statistics with selectable time range under Statistcis > Graph. You can check CPU load, memory usage, network load, etc.

3.1 Realtime load

AG-702-web-realtime-stat-a.png

3.2 Statistics interfaces

AG-702-web-statistics-interfaces.png

3.3 Statistics memory

AG-702-web-statistics-memory.png

3.4 Statistics processor

AG-702-web-statistics-processor.png

3.5 Statistics system load

AG-702-web-statistics-system.png

4. Using the terminal

The AG-702 has a built-in bash terminal. With it you can execute all commands in the OpenWRT system. To enter the terminal, go to the tools > terminal section on the built-in website. The default password is the same root/root.

AG-702-web-terminal.png

5. Reset and default

5.1 Make factory default

To reset the system to factory settings, hold down the "Default/Reset" button for more than 5 seconds while the device is operational. During the factory reset, all LED indicators will light up for 2 seconds.

5.2 Reset device

To restart the gateway without disconnecting the power supply, press and hold the "Reset/Default" button for less than 5 seconds. During the restart, 4 LED indicators will light up for 1 second (IN-1, IN-2, RS485, RS232)

Do not hold the button for more than 5 seconds, as it will trigger the gateway to restore default settings.

Cellular Configuration Manual

1. Cellular modem

1.1 Modem

The Gateway in its basic configuration is equipped with an LTE modem that also supports GPRS and SMS functions. Different modems were used depending on the model variant. Here is a table of models. 

1.2 SIM card

The Gateway supports two nano SIM cards, both 1.8V and 3V. The card connector is tray type. When installing the SIM card, pay attention to the correct insertion of the card. The used SIM card tray is designed so that the card sticks to the tray. This make easily insert the SIM regardless of the position of the Gateway.

2 Using cellular network

The AG-702 has a built-in SIM Switch app. To connect to the Internet using SIM Switch, follow this guide. We recommend using the SIM Switch app, but you can also start the modem manually by following the instructions below.  Do not use both methods at the same time.

2.1 Manual modem configuration

To activate the LTE modem, go to Network > Interfaces and select the lte tab there.

Mostly the network operator requires you to enter the APN, sometimes it also requires a username and password. Enter the required data and save.

AG-702-web-network-interfaces-config-lte.png

Then go to System > Custom Commands and click on Start modem with SIM1/Start modem with SIM2. Depending on which SIM card you want to start.

AG-702-web-custom-commands-sim-1-2.png

The modem will start up and connect to the Internet. To check if it is working properly and what the signal is, go to Modem > Information about 3G/4G/5G connection. When the modem starts up, the LEDs showing the signal strength will also light up. This makes it easy to see the signal strength in a particular location.

AG-702-web-modem-information.png

2.2 Cellular modem ON on start

To make the gateway automatically connect to the Internet after startup, you need to add a modem startup in the System > Startup section under Local Startup, add a line before line 'exit 0'.
/usr/commands/start_modem_sim1.sh or /usr/commands/start_modem_sim2.sh. Then save the changes. After each reboot, the gateway will automatically start the modem with the selected SIM card.

Remember, if you're using the SIM Switch app, don't set up a startup script.

2.3 SMS

To test the SMS operation, the gateway has an SMS interface installed. Under Modem > SMS Messages. There you can check sent and received SMS. Be sure to enter the phone number together with the country prefix, but without the + sign. The maximum number of characters is 160. The system does not support alphabets such as devanagari. The maximum number of messages in the inbox is 20.

AG-702-web-modem-sms-rec.png

For send SMS go to Send Message tab.

AG-702-web-modem-sms-send.png

Modbus and Serial Configuration

The Gateway has a very advanced Modbus master application with a convenient graphical interface. Below are the capabilities of the application:

The Modbus Master application is optimized for industrial use, allowing you to easily configure communication parameter, define polling schedules, and integrate Modbus data into your automation or monitoring workflows.

A detailed guide to Modbus Master configuration is available here.

1.1 Modbus Fundamentals

Modbus is an industrial communication protocol used to exchange data between a client/master and one or more server/slave devices. The client starts the request and the server returns the requested data. This guide only covers the Modbus TCP and Modbus RTU functions used by this Modbus Master application.

Modbus TCP Uses Ethernet/TCP networking. Configure the slave IP address and TCP port. Port 502 is the standard Modbus TCP port.
Modbus RTU Uses a serial communication link such as RS-485. Configure the serial port and the serial communication settings to match the slave.

Always start with the slave manufacturer's Modbus map. It tells you the communication settings, slave/unit address, function code, register/coil address, quantity and data format required for that device.

1.2 Select the Communication Method

Requirement Use What the user connects/configures
Slave is on an Ethernet/IP network Modbus TCP AG-702 Ethernet → network/switch → Modbus TCP slave; configure IP address and port.
Slave is a field device on a serial bus Modbus RTU over RS-485 AG-702 RS-485 → RS-485 slave bus; configure serial port, baudrate, data bits, parity, stop bits and slave ID.
Slave requires point-to-point serial Modbus RTU over RS-232 Use the AG-702 RS-232 interface only when the slave and application support that serial interface.

Do not mix the settings. Modbus TCP uses an IP connection; Modbus RTU uses serial communication parameters.

1.3 Wiring & physical connections

Use the examples below as connection patterns. Exact connector names and polarity markings must always be checked against the connected device's own hardware manual.

Example A — Modbus RTU over RS-485 (2-wire)

tw-wire-rs485-wiring.png

Use Use the AG-702 RS-485 interface with a compatible Modbus RTU slave.
Cable Use a twisted-pair cable suitable for RS-485. Keep the bus physically ordered and avoid unnecessary long stubs.
Termination For a properly terminated bus, termination matches the cable impedance; Schneider recommends 100–120 Ω at the two physical ends of the RS-485 network where required.
Biasing Failsafe biasing may be required when the bus can be left electrically idle. Only one node should provide the biasing.
Example B — Modbus RTU over RS-232 (point-to-point)

RS232-wiring-diagram.png

Important: RS-232 is a point-to-point serial interface. Do not use an RS-485 bus wiring model on an RS-232 port. Match TX/RX/GND and the slave's serial parameters exactly as specified by the slave hardware manual.

Example C — Modbus TCP over Ethernet

ethernet-wiring-diagram-modbus.png

Use Connect an AG-702 Ethernet interface to the IP network containing the Modbus TCP slave.
Configure Use the slave IP address and TCP port in the Modbus Master application. Port 502 is the standard Modbus TCP port.

2. Modbus Deployment Scenarios

These diagrams show how the AG-702 can collect data from multiple RS-485 Modbus RTU slaves and multiple Modbus TCP/IP slave devices.

2.1 AG-702 Mixed TCP/IP & RS-485 Deployment

modbus-tcp-ip-ethernet.png

In this example the AG-702 is the central Modbus Master. Five RTU slaves share one RS-485 daisy-chain connected directly to the AG-702 RS-485 port: three slaves are shown on the left and two on the right. Four separate TCP/IP slaves connect through the Ethernet network on the AG-702 LAN side.

RS-485 side — five RTU slaves
  • All five devices connect to the AG-702 RS-485 port.
  • Three slaves are shown on the left and two on the right.
  • All five share one RS-485 daisy-chain.
  • Each slave has a unique Slave ID.
Ethernet side — four TCP/IP slaves
  • TCP/IP Slave A, B, C and D are slave devices.
  • They connect to the AG-702 LAN through the same Ethernet network.
  • Each slave has its own reachable IP address.
  • They are not gateways in this example.
Device group Physical connection Protocol Addressing
RTU Slave 1–5 AG-702 RS-485 → shared A/B bus Modbus RTU Slave IDs 1–5
TCP/IP Slave A–D AG-702 LAN → Ethernet network → slave Modbus TCP IP address + device/unit identifier as required

Important: RTU slaves are connected to the AG-702 RS-485 port. TCP/IP slaves are connected through the AG-702 Ethernet/LAN port. These are two separate physical communication paths.

2.2 RS-485 Daisy-Chain Wiring — Multi-Slave Field Example

A single AG-702 RS-485 port can serve multiple Modbus RTU slave devices on one shared two-wire bus. Connect A (D+) to A (D+) and B (D−) to B (D−) throughout the chain, assign a unique Slave ID to every device, and install a 120 Ω termination resistor between A and B only at the two physical ends of the bus.

RS485-daisy-chain-wiring.png

Important: RS-485 is a shared two-wire bus. Keep the topology physically ordered as a daisy-chain, keep drop cables short, connect A to A and B to B consistently, and place 120 Ω termination resistors only at the two physical ends of the bus.

IoT platform integration

Zoho IoT integration

Integrating the AG-702 gateway with Zoho IoT is very simple. To do this, follow the instructions on the Zoho IoT website link.

Firmware update

The system can be updated via the built-in website. We can update OpenWRT firmware both when the system is running and when it's in U-Boot mode. In cases we need to have a firmware file with a new system compatible with this gateway model. Uploading the incorrect image may cause the device to malfunction.

When OpenWRT is running

Go to System > Backup / Flash Firmware. At the bottom of the page is an option to Flash new firmware image. Select the correct system image and click Flash Image. 

AG-702-web-update-firware.png

This is followed by a firmware file selection window. 

AG-702-web-update-firware-select.png

Select the correct file and click upload.

AG-702-web-update-load.png

The file will be loaded into the gateway and verified. If it is verified correctly it will go to the window where the option "Keep settings and retain the current configuration" will be checked. If you do not care about keeping the configuration, it is better to uncheck this option. 

AG-702-web-update-conform.png

Then you have to wait a few minutes for the system to load and update.

Do not turn off the gateway while the system is being updated. This will damage the system.

By U-Boot mode

This method of uploading firmware should only be used when the system is not working and the firmware cannot be uploaded in the normal way. To enter U-Boot mode press RESET switch for 4 seconds when switching on the power supply. The Gateway should start on U-Boot mode. In U-Boot mode, the white STAT LED glows continuously. To access internal website go to IP 192.168.10.50 and load firmware from proper firmware file provided by Atreyo. 

Uploading incompatible firmware not provided by Atreyo will void the warranty.

AG-702-web-uboot.png

Then you have to wait a few minutes for the system to load and update. 

Do not turn off the gateway while the system is being updated. This will damage the system.

Firmware list

The Gateway works on the OpenWRT operating system. The operating system is specially prepared and compiled for hardware. So when it is booted up, it is ready for use. In addition to the pre-installed application, we provide our own repository of free apps compiled for this Gateway. We update the system regularly to keep the latest version. You can check the latest releases here.

V1.01.05

With built-in Modbus Master. IPV6 support added.

AG-702-LT-EU version

Firmware Version File name Kernel
 OpenWRT
 Date
V1.01.05a download
 5.15.71
08.01.2025

AG-702-LT-GL version

Firmware Version File download
 Kernet
 OpenWRT
 Date
V1.01.05a download 5.15.71
08.01.2025
V1.01.05a

Add pendrive support (kmod-usb-storage)

AG-702-LT-EU version

Firmware Version File name Date
V1.01.05a atreyo-openwrt-AG-702-V1.01.05a-EC200 11.03.2025

AG-702-LT-GL version

Firmware Version File name Date
V1.01.05a atreyo-openwrt-AG-702-V1.01.05a-EG25 11.03.2025
V1.01.07

Add QMI communication with LTE modem.

AG-702-LT-EU version

Firmware Version File name Date
V1.01.07 atreyo-openwrt-AG-702-V1.01.07-EC200 05.04.2025

AG-702-LT-GL version

Firmware Version File name Date
V1.01.07 atreyo-openwrt-AG-702-V1.01.07-EG25 05.04.2025
V1.01.09

Changes:

AG-702-LT-EU version

Firmware Version File name Date
V1.01.09 atreyo-openwrt-AG-702-V1.01.09-EC200 23.08.2025

Safety information

Operating environment

Use in inappropriate conditions may damage the device or shorten its life.

Electrical and power supply safety

Only a person with qualification and appropriate knowledge should install the device.

Malfunctioning and damaged device
Radio frequency exposure

This device has been designed and manufactured not to exceed radio frequency energy emission limits set by regulatory agencies. To comply with RF exposure guidelines, the device must be used at least 20 cm away from a person's body. Failure to follow these instructions may result in exceeding the applicable RF exposure limits. This only applies to models with a built-in LTE modem.

What to do and what not to do