I did some intensive exploration and research on the EX-Link serial protocol. Documented my journey at the github link below. Attempted to get a basic understanding of sending and receiving ex-link commands.
Forgot to post this awhile ago case people were looking for more help with ex-link serial on Samsung TV’s, hope it helps. Recovered newer spreadsheets not available any place else. I also go over how to find some codes not listed in the sheet with the debug feature.