Not quite sure how a UPS can foul up a x10 signal.
I would think they prevent noise from going back onto the network.
I have four of them and they are all on circuits that the X10 cm15a controls.
The PC that has AHP installed and is connected to the cm15A is on a UPS.
In fact the cm15a is plugged into a power strip that is plugged into a UPS.
A TV on the UPS? That is some very serious television watching!
I bought a new 1500Va model for my main business computer and took the old 425VA model to use on the Direct TV receiver, TV and stereo.
It has come in handy many times during storms.
The Direc TV receiver nevers loses power and so it never needs to be re-set up.
UPS's eliminate voltage spikes, brown outs, etc and protect equipement.
I have been wathching TV during a storm and then the power went out but I was still watching TV.
I would never run my computers without being connected to a good UPS.
Seen too many computers crash because they were writing data during a brown out or power bilnk.
Not only that, I run a couple server programs that cannot lose power at any time.
I also have a small weather station that uploads to the web every 15 minutes.
And of course, there AHP that I control via the web and it is running 24/7.