[sdiy] Sending Digital Commands Over Your House's AC Wiring?

[Dave Manley]

Google: HomePlug Powerline Alliance

Or take a look here:

http://computer.howstuffworks.com/power-network.htm

I'm running a slower speed version of the Ethernet over Powerline for 
part of my house - only because there is no crawlspace and no attic for 
wires, and wireless wasn't available at the time (and I've been too lazy 
to upgrade it).  You get what looks like two wall-warts, but they have 
RJ-45 connectors on them.  Plug them into two outlets and you have a 
network.  The only problem I had was needing to move one of them away 
from the circuit that had the electric dryer, which must have been 
generating some kind of electric hash.

-Dave