Metcalfe: IP over power lines

Rohit Khare (
Tue, 11 Feb 97 15:59:59 -0500

Is Bob reading FoRK-archive...?


Still, definite kudos to Michael Propp for prescience.

(rajit: do you think alain would care?)


February 10, 1997

Cheap, reliable, powerful 'net connections may be as close as an electrical socket

What we need is competitive, dedicated, multimegabit Internet everywhere, and
we need it soon. And not just in basements, which is hard enough to get
thanks to telephone monopolies, but in every nook and cranny of every room
everywhere, especially homes.

Well, there are now again reports about the Holy Grail of network plumbing, a
promising but heretofore elusive way to get the Internet we need without
rewiring the whole joint.

Before grabbing the Grail, let me emphasize that we need competitive plumbing
of many kinds. Competitive, because we want our Internet soon, and we want it
evolving rapidly after that, on Internet rather than telco time. We want it
everywhere soon and cheap, unlike the digital services long promised, slowly
deployed, and now at last overpriced by monopolies under government

We need dedicated Internet access because digital data packet switching on
top of analog voice circuit switching is such an abomination that dial-up
modems hiss and squawk every time we force them to do it. No more dialing, no
more busy signals -- future America Online users, if there are any, would
appreciate that.

And we need multimegabit Internet access. Already 56Kbps is a drop in the
World Wide Web's bucket. We'll eventually want video telephony via our local
loops. Maybe we'll be properly engineering Internet servers and backbones by

Now telephone and television wires are not the only plumbing that will
compete in getting us Internet everywhere. There are the many forms of
wireless, which I'm rooting for but tend to discount. And there are the copper
wires that already reach all rooms in all buildings everywhere, wires with
which all PCs, printers, servers, and routers are already connected. I'm
talking about the ubiquitous electrical powerline network.

Imagine plugging your computer into any power receptacle and having it
immediately on your home's multimegabit intranet and therefore on the
Internet. No separate network cables and jacks.

Powerline has been the Holy Grail of ubiquitous computer networking. Michael
Propp, president of Adaptive Networks, in Brighton, Mass., has been pursuing
powerline since getting his doctorate in physics from MIT and starting
Adaptive with his brother David in 1983.

Today, Adaptive's 15 people are the Intel of powerline networking for
refrigerated cargo containers. Propp says there are 40,000 new refrigerated
containers each year, half of which are networked, thanks to Adaptive.

As containers are loaded onto ships, their refrigerators are plugged into
diesel generators. They then network through that noisy powerline to have
their temperatures controlled by a PC on the ship's bridge.

Adaptive's technology has been adopted by the International Organization for
Standardization (ISO 10368). Adaptive's powerline products, some now operating
at 100Kbps, are also being used in vending machine monitors, point of sale
networks, utility telemeters, industrial material handling robots, public
transit vehicles, factory automation tools, and, yes, residential networks.

Adaptive uses its own nonmultiaccess variant of emerging spread-spectrum
technology. Its transceivers get through the contortions of power cables with
diesel noise generators, hair dryers, and light dimmers. Adaptive allows
multiaccess using a clever system based, not on Ethernet, but on token
passing, which -- if you remember Datapoint's Arcnet and General Motors' Token
Bus -- does often work.

The reasons powerline's time may soon come are three-pronged. Spread-spectrum
signal processors such as Adaptive's, which promise to get through powerlines
at megabits per second, are becoming affordable. More than one-third of
American households have PCs, so now there's a critical mass of home devices
worth networking. And we do want the Internet everywhere, dammit.

Eventually we'll need powerline transceivers on the motherboards of our
clients and servers to network them cleanly through their own power supplies.
Longer term, we'll need cleaner powerlines to carry ever higher bandwidths.
Shorter term, let's have cards, cables, and transceivers to drive powerlines
through today's standard hardware interfaces.

We need powerline-connected routers to put our homes on the Internet through
a variety of competing access technologies. Some of these will bypass telcos
by using demonopolized metropolitan-area powerline access through power pole
transformers and substations.

If you're pursuing powerline networking, let's hear from you. If you'd like
to explore applying Adaptive's technology or otherwise help Propp expand his
company, see or call (617) 497-5150.