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

[Jason Proctor]

digital comms over power lines gets publicity or traction every now and again.

a bit of googling turned up this ---

http://www.networkworld.com/newsletters/lans/2006/1030lan2.html

my old roommate worked on a system for Farallon a decade ago, which 
IIRC suspiciously had the same name. maybe D-Line bought the product 
from the ashes of Farallon.

offhand i'm not sure why it doesn't have more adoption. although it 
is a little awkward if the house has more than one mains circuit!


>I have a question that I've been wondering about for at least 25 years
>because it seems very bizarre and I've never heard of anything else on
>earth working this way.  I have an expensive Anova phone/control
>system from the early 80's.  In addition to the phone, it has has a
>security system unit that works with sensors placed about your home,
>and also a home appliance/lighting control unit for turning things on
>and off automatically.  To use that last unit, you plug these modules
>into the outlets, which they themselves have outlets on and you plug
>what you want to control into them.  You set the device number from 1
>to 16 for each of those modules.  The main control unit communicates
>with these modules that are plugged in all over your house by sending
>commands over the house's AC wiring.  I've never known AC to be used
>for anything other than power.  I just can't imagine how they're
>sending commands out of the AC power cord, into the house's wiring,
>that is then read by the modules.  Just as the manual says, if I try
>to plug the main controlling unit into an isobar with its filtering,
>it doesn't work, the modules won't respond to commands.  Technically,
>how are they doing this?  Imagine synths sending MIDI data to each
>other through their power cables.  That's how weird this is.
>
>Puzzled,
>-Ken Elhardt
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