I agree with skipo that you may be wrong about the one phase thing. If you have a dryer or oven you home that is run off of electricity, you have two phases.
My first thing to try would be to move the IR543 around and try it in different plugs. If you can get the units to work when the IR543 is plugged into a different outlet, you may need a coupler.
As MMMfishies states, your problem could also be due to noise. Try unplugging all computers, baby monitors and TV's. Then try the IR543. It you get a response from the units, you may try plugging in a unit at a time and trying the command again. If you get to a point where it does not respond, try unplugging the last unit. If it works again, you may need to install a filter on the device.
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www.x10ideas.comChris Couture
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