Choosing between products

BBQKees Electronics offers two types of products to interface with the EMS bus: Gateways and interface boards.

Interface boards are only a pure hardware board that translate the EMS bus signal to a UART serial port signal and vice versa. You need to connect a microcontroller to these boards and install or write your own software to interact with the EMS bus.

Gateways are a complete plug and play package that you can connect to the bus via just one cable or two wires and they provide an easy to use web, MQTT or HTTP interface to communicate with your home automation.

Choosing between a Gateway and an interface board

If you want to have all your boiler and thermostat data into your home automation like Home Assistant, Domoticz etc with only one cable and with only minimal configuration, then pick a Gateway. If you like to play around with electronics, solder stuff and mess around with Dupont wires, or you want it a bit cheaper but less nice, you can choose one of the interface boards.

Like mentioned above the interface boards are just a piece of hardware. It comes with no microcontroller or software.

Choosing between Gateway models

At this moment one Gateway model is available:

  • Gateway S32 (Standard edition) = WiFi
  • Gateway E32 (Ethernet version) = WiFi + Ethernet (Discontinued)

The Gateway S32 is the most current model based on the ESP32 microcontroller.

A new model with Ethernet is expected around November 2023.

Gateway S32 (Standard edition)

The Gateway S32 (S=Standard edition) is the latest Gateway model based on the ESP32 microcontroller.


  • Based on the ESP32 with 16MB flash
  • EMS-ESP firmware version V3.5 and up
  • Plug-and-play connection to the EMS bus with one cable
  • Connects to the EMS bus via the service jack or the EMS/thermostat wires
  • 2.4GHz Wi-Fi connectivity
  • Complete responsive webinterface
  • Firmware updateable via the webinterface
  • Configured for Home Assistant
  • Supports the Home Assistant MQTT Discovery protocol for Home Assistant, Domoticz and OpenHAB.
  • MQTT and Restful API for other interfaces like Loxone
  • Telnet console
  • Optional DS18B20 temperature sensors
  • Supports all EMS heating circuits
  • Supports EMS systems with multiple EMS devices simultaneously
  • Support for EMS, EMS+, Heatronic 3 etc.
  • Can be powered via the service jack or a 12V DC power supply.