FWIW, I have experienced one incompatibility with the Edgeport (on a Windows PC). I have an RS232 to RS485 converter and the Edgeport refuses to work with it. I used its configuration utility to tweak a few parameters but no joy. So I bought a USB-RS232 cable with an FTDI chip and, out of the box, it also didn't work with the RS485 converter. However, the cable's configuration utility allows you to tweak a broader range of operating parameters and I eventually found the right combination to make it work. I intend to purchase the same cable for use with the Pi.
EDIT
I really want to make this work reliably. It'd be a damn shame if this serial port instability issue derails my entire project. I don't relish having to implement it using a traditional programming language, especially given the progress I've already made using Node-RED. It allows me to focus on the task of converting the UPB protocol as opposed to managing the needs of serial and MQTT communications.
