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Digital Power Line Gets Buried 40

vyzar writes "NOR.WEB Ltd, the joint venture between UK telco Norweb Telecom and Nortel Networks developing Digital Power Line technology, for carrying high-speed data over electricity supply lines, is being disbanded, and the technology dumped. Norweb Telecoms say that the technology has been "proved", but the project was disbanded for financial reasons. The fact that the technology leaked high levels of radio frequency in frequecy bands used by the UK emergency services, military, and radio hams; and that it was fighting an uphill battle with the UK radio licensing authorities, did not appear to be mentioned in news reports. "
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Digital Power Line Gets Buried

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  • Even if the signal didn't leak out - making the powerline-borne signal just another copy of what's in the aether - it would still have been one big party line - with the whole world on it.

    By comparison, a T3 propagates on a coax cable, not leaky open lines, and it's good for less than half a 100 Mbps LAN, less than a 20th of a gigabit ethernet. Neglecting compression, it's only good for 116 phone calls or 56KB to 64KB data links, or 28 T1 connections.

    This thing would have been a drop in the bucket.

    Raise your frequency and you get more data but less range (and more leakage) - requiring the addition of repeaters all over the place, and thus eliminating most of the advantage of using the installed base. (And you also need a mod at every transformer to get the higher frequency stuff passed from one side to another of a device designed for low audio frequencies.) If you're going to send a lineman out to add equipment for each cluster of a half-dozen homes, why not just string some fiber while you're at it?

  • >>"The power grid is designed to deal with 50/60Hz frequencies only".

    I fail to see your point. How about frequency modulation? How about a signal transmitted in frequency that has an average in time that fits with your 50/60 Hz sinusoidal curve?

    I think the idea is good. The only thing is that in theory, practice and theory are the same, but not in practice...

  • Two developments. MIMOS (Malaysian Institute of Microelectronics) are attempting to make available computing-on-tap technology - the idea is [equivalent to turning] on the tap and out comes computing. See the article in MSC Times [].

    In another development Malaysia's power company Tenaga Nasional Bhd. [] will be offering telecommunication services over their power lines using DPL technology starting next July. See the article in The Star (Malaysia) newspaper []. I hope they won't have similar problems to Norweb :)

  • There are a few companies out there with X10 style interfaces for networks. Usually the bandwidth is under 1 Mbps.

    There was a company with a claim of exobit speeds a while back, and was completely shredded by the slashdot community. It was either a hoax or rogue marketing droid.

    The new bluetooth wireless lans and Apple's AirPort are going to be a cheap commodity product soon enough, the way ethernet has sort of become the defacto standard at the moment.

    the AC
  • by WasterDave ( 20047 ) <davep.zedkep@com> on Friday September 10, 1999 @12:35AM (#1691498)
    We're going to get sheets and sheets of "told you so" messages, some of which will carry the "powerlines as an antenna" analogy.

    Fair enough, it all went shed shaped, but you have to give them credit for looking beyond the end of their noses. Consider for a second the following bits of conventional wisdom:

    * In a few years we may have computers that can perform tens of thousands of calculations, per second !!! (excited and drooling scientists circa 1960).

    * Nuclear power will be too cheap to meter (other excited and drooling scientists circa 1960).

    * A free operating system will never be as good as a proprietary one (drooling Microsoft executives circa 1995).

    * Many millions of computers, worldwide, will all be connected to the same network.

    So we have some vast understatements, some over simplifications and one blatantly incorrect. But in amongst this company "we think we can get half a dozen Mbit/s down power lines" isn't that an outrageous a claim.

    And the prize, had they made it work? Dead telcos. 80% of their business anyway. A nearly immeasurably large quantity of income for the next god-knows-how-long.

    Nice try. Back to shining lasers from one rooftop to the next.

    Dave :)

  • You'd better not plug your computer in then - it'd be hooked up to the mains which is a "very bad idea"
  • Looks like my mind goes into random fact mode when heavily deprived of sleep. (I'm literally having eye spasms here. Somebody save me and patch uulib/mmencode directly into SLiRP and pppd for me).

    Anyway, undersea copper cables carry so little traffic relative to fiber that they're no longer used for data transmission--some scientists have been taking them over as a means for analyzing the earth's magnetic field. In other words, lets see what happens when we do nothing to them...we've come along way since when once of the first(*the first*?) transatlantic telegraph cables was literally burnt out when the scientist operator on one end was so obsessed with getting voice signals over a cable never intended for such that he jacked up the voltage higher, and higher, until boom...

    Then again, maybe we haven't come that far *after* all...;-)

    "Sir! Sir, our transmissions from the NSA are being interrupted god, will somebody get that 16 year old out of that alt.binaries group? We'll be down for hours!"

    Yours Exhaustingly,

    Dan Kaminsky
    DoxPara Research

    Once you pull the pin, Mr. Grenade is no longer your friend.
  • First of all, the power lines are not intended for data transfer. They are intended for power transfer. This means that:

    • There is no shielding.
      Disturbances leak in at free will, and also they leak out (which means radio interference).
    • There are no filters.
      A TV, microwave oven or a welding unit generate lots and lots of disturbances, which goes out on the grid unfiltered (well, to the nearest transformer station anyway).
    • Different conditions for each house.
      The line from the last transformer station (where the data is moved to/from a real data communications line) to the individual houses can be ten meters or 500 meters. There can be one household or thirty on the same line. This means that the conditions vary wildly from house to house, and it is very hard to create a transmitter/receiver that will work everywhere, since they are typically optimized for a fixed line condition.

    These things, and several others, means that yes, you can communicate over the power lines, if you have a short line to the transformer, and if your neighbour doesn't turn on his TV, and if you don't care about airplanes dropping from the sky because you confused their tracking system, and so on.

    There are a few test systems in use here in southern Sweden, just intended for reading the power meter remotely. These systems communicate with around 1200 bits/second, and use small packages (I think it was less than 40 bytes). Each packet is retransmitted up to four times. Even so, they have an average packet drop ratio of 40 - 100 percent. Yes, that's 100% corrupted packages.

    My opinion about all this is: Keep power in power lines, data in data lines and phone calls in phone lines. That's what they were designed for.

  • This was an ongoing saga, first published by some famed media hackers, then confirmed by a handful of groups, then denied, exposed as a hoax, then confirmed again.

    If you read Need To Know now, you can track this saga as it pops its head up in various magazines at various times. Typical internet bizarness familiar to slashdotters, where a good story gets repeated by legitimate news outlets with no fact checking. I still haven't made up my mind on this one :-) 515.txt

    the AC
  • Instead of trying to run both a high-power low-frequency signal and a low-power high-frequency signal through the same cables (duh), use the power lines as a messenger wire for an all-dialectric fiber optic cable. There's even a company which has a machine that rides along the power line and wraps fiber optic cable around the power line.
  • If this had been successful then it'd just benefited the companies (i.e. cheaper for them, more profit).

    Something which would benefit consumers would be the use of internal electricity circuits as a home/office network. No installation hastles, no expensive cabling... I'm sure I read about his somewhere.
  • So the technology didn't work out; big deal. Okay, so the companies lost a tonne of money on the project (probably), but these things'll happen. Not every technology works, and we should be grateful that companies are willing to risk things like this happening; this way lies progress.
  • I read on New Scientist, that it also interfered with the street lighting and caused the lamp posts to flicker. Hmmmm, this would have interesting consequences. Snooping on others with photo diodes, anyone?
  • Here in Sweden, it was demonstrated a year ago that it worked on a distance of a few 100 meters and that, due to inter channel interference, you only could have one transmitter per three phase power suplye to a house.
  • Problem is that with our society, more important things usually get precedence, like viagra
  • Actually, the /. article title poses a possible solution to the RF emission problem.

    BURY the lines and you should have little or no emitted RF.

    I can't speak for the flickering lights, however.

  • Erm.... did you read the information on Norweb's site []?

    "In effect, it turns the low voltage segment of the existing power distribution infrastructure into an Intranet and the customer is provided with a Local Area Network for home or office use."

    Nuff zed. =)

    This isn't the post you're looking for. Move along.
  • It's not very often that you see companies actually announce that they're dropping something.. usually it just kinda fades from memory and someday someone asks "Whatever happened to..."

    What about doing networking in your house through power lines, though? Maybe they could take the technology they developed here and adapt it for that (X10 on steroids).

    Wouldn't there have been security concerns, what with your traffic being on the same wires as basically everyone else who's using your power station? Their web site says they take the Internet service from a local substation right into your house... Unless they installed filters somewhere outside my house, my neighbor's traffic would be there too...

    Tho I guess we have that now with cable modems and we don't seem to mind.

  • This is a proven technology in the lab and field. Part of the reason Nortel dumped this is because of direct competion in there DSL and Lan City Cable Modem divisions.
  • This is being done... I'll try to find a link, but it is being used for some "home" LANs.


    Time flies like an arrow;
  • It's a nutty idea anyway to transfer a MHZ range signal through an unshielded power line. The power grid is designed to deal with 50/60Hz frequencies only ... Btw., the technology itself has been known for some time - the serbian army was rumored to run parts of it's military network (air defense in particular) through it's (highly redundant) powergrid. Thats partly the reason why the US used carbon bombs to disable the power grid for a few hours. Obviously a military network is not nearly as bandwidth-hungry as millions of households browsing /. ;)
  • by Anonymous Coward
    Get background info on the radio intereference aspects here [] .
  • by Effugas ( 2378 ) on Friday September 10, 1999 @12:15AM (#1691518) Homepage
    Supposedly--mind you, I'm a city boy, so WTF do I know--large chunks of the cross country power grid are just unshielded solid cable. Why pay to insulate over those kind of distances, when you can just shove the cables up pretty high and hope nothing like a large-winged eagle will short your cables...

    "KFE: The Official Dinner of BFE."

    The point is, sometimes when you design to the minimum specification, things get burnt. Most power grids were designed for tossing out 60hz AC at the endpoints. Higher frequency artifacts were just never considered in the design specs. So basically we're left with an infrastructure that truly *is* universally available(power company goes *almost everywhere*, because private power is still expensive--this'll change), but we can't use these wires all over the place because of a failure in foresight.

    The most powerful example of not seeing where things were going involves Sprint--as far as I've heard, which, again, probably ought to be verified, is that when they laid their thousands of miles of cable they only put in a few strands apiece. All the money was spent doing the truck roll...and barely anything on expandability for the future.

    There's a lesson here. We all seem to thing where things are going. I think technologists need to start quantifying the degree of unsurity in technological prediction, so that companies like Sprint and Nortel can evaluate their decision makings on much large timespans.

    Well, at least that's what I think.

    Yours Truly,

    Dan Kaminsky
    DoxPara Research

    Once you pull the pin, Mr. Grenade is no longer your friend.
  • Over here on the east coast the power companies are already embarking on a similar system. They are replacing the static lines on the towers (the top wires designed to take the lightning strike) with cable with fiber optic cables down the middle.

    As the information running down the fiber is in the form of light there is no interference from the power lines.
  • This link, [], has many press clipings about this type of LAN for the home... good information and several reviews... Baggio
    Time flies like an arrow;
  • I'm somewhat disappointed. I hadn't heard anything about it lately, and was just thinking about it a couple of days ago for some reason. I thought that it would be a great way to distibute information all over the country. Kinda like X10 units, or the devices you plug into an outlet to use the household wiring as a large antenna. But obviously at a much higher scale.

    What would it do to the power grid though? The power comapny has large capacitor banks to counter any inductance introduced by factories/neighborhoods. I guess it's not a capacitive or inductive signal, but I can't imagine that that kind of signal on the utility lines would be all that easy to isolate, and provide the clean sinewave required by some equipment. I guess since it isn't going to happen, these aren't major concerns anymore.


    Time flies like an arrow;
  • So basically we're left with an infrastructure that truly *is* universally available(power company goes *almost everywhere*, because private power is still expensive--this'll change), but we can't use these wires all over the place because of a failure in foresight.

    Rather an expensive form of foresight, though...

    Several years ago, someone in the UK found a more innovative way of using the power grid for telecoms. Instead of worrying about using the wire itself, they strung fibre optic cable round the large pylon-carried cables national grid - a cheaper way of making a national telecoms network than burying the cables...

  • I'm interested in hearing what everyone has to say about media fusion, which is boasting about its upcoming technology (that hasn't been tested yet). I'm curious how they can get around some of these difficulties in interference.
  • This was a great posting. Normally, all we get in commentary is "this is soo cool". Here the poster (vyzar) added a significant nugget of information.

    Insights like that are why I read slashdot.

  • This was never going to work, and won't work anywhere else, either. They are simply going to radiate those signals into the air and what you end up with is radio.

    Radiation from DSL, which uses balanced twisted pairs, much less likely to radiate, is still a problem. To think that this would work on poorly balanced, non-twisted power lines over long distances was a pipe dream.



    P.S. My home alarm, phone, and data wiring is on shielded twisted pair.

  • I work for an electric company that started offering dial up Internet service. I hold the position of managing the Internet services. One of the main problems facing our small operation is the ability to offer broadband. There are basically two main contenders in our area, cable modems and DSL. The problem with cable modems is it is owned by the cable company and so they have a lock on that infrastructure and market. The problem with DSL is it is controlled by the phone company and then resold through third parties. And dealing with the Phone Company is very difficult with just the dial up lines for modems that we use. They are slow and unresponsive and we take the heat for their mistakes. All of this would be solved if we could utilize our own infrastructure, i.e. the power lines. Adding a third competitor to broadband would seem to benefit consumers.
  • Most of the UK uses buried powerlines. As the DPL trials were in urban areas, and used substations as local hubs, the street-light flicker would have been induced at a distribution level. There were many security concerns as a result of this distribution model - and contention levels were higher than for alternate broadband techniques.

    Interestingly, a friend in Bath builds HiFi components, and has discovered that one of the biggest sources of noise in his system is the daily DPL data dump from the local substation to the SWEB control centre in Bristol.

  • Many power companies run a fiber network along the top of their powerlines for inter communications with their substations. These main power lines do run by everyone's home though. The problem lies in the last mile to the customers home and the cost for the electronics that sit at the end of the fiber.

CCI Power 6/40: one board, a megabyte of cache, and an attitude...