This page is for people who have Efergy power transmitters who want to interface them directly to Home Assistant without having to use the Efergy website and API (which was always unreliable, and now appears to be defunct). My notes below (as made at the time) describe what I did to get it going. I was amazed I was successful because I didn’t really understand what was going-on, and just following stuff I found on Google. So the notes are just about the full extent of my knowledge at the time of implementation – and any other information not recorded at the time has almost certainly been forgotten!
So – for what they are worth – my notes.