@David-TP The RE505X’s hardware version is 1.0. Yes, the AX20 is connected only to a wired router, which in turn is connected to the modem. That is called a cascade setup. I have always used this...

@David-TP No, the RE505x was never hardwired to the AX20. However, your question led me to try something more and I found that the network interference disappears if I remove the cable linking the...

@David-TP Yes, the symptom is fully reproducible: interference starts a few seconds after the extender is plugged-in and stops immediately when I unplug it. My Wi-Fi router is a brand new AX1800...

@David-TP I have an RE505X that is causing network interference exactly as described in this post. Should I use the beta firmware labelled RE105_V5 ? (It looks like the closest model to the the five...