DMX with serial object and Enttec USB

Up until recently, I had been searching high and low for a good solution to working with DMX over USB. There's a lot of information, but it mostly seems to center around Artnet or a no-longer-available external (for Catalina) on nullmedium.de. It took me quite a while to figure it all out, so here's the simple solution I wish I would have found at first. I hope this pops up early in the search results!

It seemed to me that DMX should be simple with the serial object, since DMX is basic serial commands. I found some information on Peter Elsea's site at
http://www.peterelsea.com/Maxtuts_advanced/Controlling_DMX.pdf
which was close, but seemed a bit confusing on how it organized the data.
I eventually stumbled on a git hub repo that essentially recreates the DMXUSBpro external in a serial-based abstraction:
https://github.com/thomasfredericks/DMX_USB_PRO_MAX
Here's the abstraction reposted here with some additional clean up and notes for posterity:

Here's a nice patch to create a umenu of serial ports for easy selection:

Here's a link - https://dmxking.com/usbdmx/ultradmxmicro - to the mfg site for the USB DMX solution I bought on Amazon. It uses the same FTDI serial chip as the Enttec, so it's compatible.

Thanks Thomas Ouellet Fredericks for your patch!