I recently joined this club. But have some additional info.

As stated in this topic:www.remotecentral.com/cgi-bin/mboard/prontopro/thread.cgi I have encountered the problem of the RFX busy LED. At first I thought it was ht extender that was not ok. Then I started some testing.

All the FW's are the latest. I use an XCF file I used before (and it worked flawlessly), with no changes, just a new RFX, router/AP and TSU9800. Network is with or without encription, works the same way. All fixed IP.

I started getting:
0450 Extender _ IP_ didn't reply.
0404 Extender 0 didn't acknowledge command

Then I reloaded the XCF on our "default" TSU9800 whit which I make all of the configs (yes I do it all on this, then just transfer to the client's). And ... everything worked flawlessly. Not one extender error in the Diagnostics.log.

I currently have 5 TSU9800 here and tried all of them. I had 3 different behaviors:

My (the working one), worked flawlessly and has a serial number:
PL1B .... v2.2 TSU9800

The 2x PL1C...  (v2.2 TSU9800) had the greatest number of failures

The 2x PL1D... (v2.2 TSU9800 - the one with the wall-mount already in the box) had a small number of failures (at the end I hardly got any).

So it seems that the newer revisions have these problems, maybe they changed something, maybe not.  The reproducing of the errors is quite random. I noticed one more thing, all of the bad TSU9800's have a warmer top (above the pronto logo) than the working (old) one.

I also noticed that this persists for some time on the TSU, during this time there is no communication with the RFX (even not all of the failed presses are logged as communication faliures with the RFX), then after some time has passed everything starts working again.

Please can you all check the SN's  of your devices, if they match the ones I provided.

Or maybe the problem really is in the extenders.