Is that actually an ethernet port, or is it just an RJ45 for something like I2C, UART or some other protocol? It's also got a little port for a Bluetooth controller, which came with my desk. I bet it's possible to reverse engineer whatever protocol that is using over bluetooth/BLE.
I have this and it works great. I wrote a script for it that checks my google calendar to make sure I'm not in a meeting (nothing worse than your desk suddenly moving positions when you're in the middle of talking to folks) and then moves my desk to a standing position for a configured amount of time every day. https://github.com/signalnine/upsy-desky-autostand
Gostand does as well. Hmm. Would they have bothered encrypting data going across that wire? Seems unlikely. Would using actual ethernet have been cheaper than DIY? Really might be. Interesting thought, I do want to toggle the desk height from emacs and probably from cron