AB modbus gateway

AB modbus gateway is based on ESP32 C3 chip. This Device has built-in WiFi + BLE to send data wireless to other device like a server or computer for post-processing or controlling or monitoring. RS485 have some standard protection on it. You can use this device in home automation too where you only have to provide WiFi in one device.



  • Directly program with ESPHOME. No need to write code but a configure YAML file instead
  • Onboard 2 Programmable LEDs.
  • Onboard Type-C USB for Programming.
  • Two buttons.
  • DIN rail + wall mount Encloser.
  • Compact Size (46.2mm x 29.6mm x 60mm)
  • Low Power.

Note: The RJ-45 connector is not designed for ethernet connection. It's used for wire RS485 pins.

Power requirement

  • Input voltage 12V DC.

GPIO table

GPIO 9Button 1, K1 for programming
GPIO 3Button 2 (K2)
GPIO 7Yellow LED
GPIO 4RS485 TX pin
GPIO 5RS485 RX pin

Pinouts for RJ45 port


Example firmware


Last Updated:
Contributors: yanc