Hi Phill<br />its a form of Home Automation were you have plug in modules ( they look like a Arlec Timer) you give them a adress with a Screw drive eg, A7 and you have a computer interface that also plugs into the same circuit and the control singles are carried across the mains so that when you tell A7 to switch state it does.<br />you can also get Batten holders modules ( they look shit) so that you can control lights as well <br /><br />Its a product from the USA and has Been used there for some time and there is a lot of stuff that is X10 as it is open source to some extent <br /><br />The clipsal Minder Controller has a X10 interface on it <br /><br />X10 as Parts go are very expensive in relation to the Australian stuff (clipsal HPM etc)and dont have as much features <br /><br />do a X10 search on the web for more detail