Hi Paul
try
Pronto buying guide?
it includes my reply not much about X10 Control, but there is also other helpful info on that thread.
The X10 capability for Prontos can be dealt with in 2 ways.
ALL Prontos can control X10 and also use IR so will work your TV etc. But they do X10 in different ways.
All Prontos will control X10 via an infrared (IR) to RF convertor (bought seperately). But not all
need to do it that way.
The older Prontos do not have RF capability. The Pronto needs something to get RF to the X10 reciever and that is the IR to RF convertor, but the Pronto and convetor have to be within line of sight for the IR from the Pronto to get to the convertor. The convertor than sends out RF signals to the X10 reciever. The X10 reciever does not then need to be in the same room.
Newer European Prontos can send RF signals (that happen to be) the same as the X10 signal sent buy the convertor (so the convertor is not needed) and uses the same X10 reciever so does not need to be in the same room.
If you get an imported Pronto from the USA, it doesn't matter how old or new, you have to use the IR to RF convertor because the US RF signals are not compatible with the Euro X10.
I currently use a Pronto RU990 and X10 and it works really well.
Hope that helps!
Stoobie