[quote="DarylMc, post: 21738"]Nice, that makes it a bit easier. Just remember if you upload a config which isn't working doesn't prove the config is OK but you will soon find out if you have a unit to swap.[/QUOTE] After unit swap, second DLT has firmware 3.0. Initial version was 2.0 DLT operational logic is now restored. So I have concluded it was a firmware bug / generic failure / loss of connectivity to incoming data. Interesting fact was that it took me 3 attempts to erase all of the button labels. That may prove consistent with my issue. It will make a good light switch despite the technical issues. I wont use the first module for data logic. Now the question is, can I send my DLT for refurbishment back to clipsal and pay a modest fee. Or does anyone know how to flash the firmware ?