This little adapter PCB is used in the SMuFF-Ifc2 project for the ESP32 variant.

The SMuFF-Ifc2 is basically a 3-way serial port splitter (if running on the ESP32) which allows controller boards like the Duet3D (or any other RRF compatible board in this regard) to communicate with the SMuFF and the PanelDue by using one serial port only.

The ESP32 version, in contrast to the smaller ESP8266, is even able letting you attach the SMuFF-WebInterface via Bluetooth, in which it becomes a 4-way splitter.

As it's obvious in the attached pictures, this PCB doesn't need a lot of components. A handful JST-XH connectors, pin headers and one (optional) resistor is all you need. The ESP32 DevKit / NodeMCU can be found in various shops. Just make sure you get the 30 pin version.

In theory, you could utilize the SMuFF-Ifc in other projects, where you face the same lack of serial ports.

If you don't know what the SMuFF is for, visit my project website here.