X10 Newbie here!!.

I've just set-up a CM12U to control and a few appliance modules from my PC.
Everthing works fine if everything is on the same mains ring, but if spread
across two mains rings, devices on different rings don't work.

I've just got a simple mains consumer unit with 2x 32amp rcd's (one for each
mains ring - upstairs and downstairs), plus some others for lighting which
i've not played with.

Is there anything basic i've missed, or any basic guidelines for fault
finding etc?

Please help!!!

Many Thanks

Jon