@David-TP after almost a week I think I discovered the problem. It's not a bad cable or a bad switch (this problem is very present in the forum and none of you have ever bothered to fix it!). Let me...

Hello. I recently purchased 3 deco x10 (one at a time) and connected them together in this way: I have 3 floors (including the garage. For simplicity I will number them in order starting from 1). the...