back to article DSL inventor's latest science project: terabit speeds over copper

John Cioffi, known as the “father of DSL”, reckons we're nowhere near the limit of copper transmission speed, delivering a presentation claiming Terabit performance is feasible. Feasible with a bunch of caveats, that is, the two most important of which are “if research delivers on theory”, and “if it can be standardised”. The …

  1. Anonymous Coward
    Anonymous Coward

    It would be an interesting development

    If it turned out those tired old twisted pair telco lines could allow for higher bandwidth than the cable company's HFC network. It would be funny if Verizon regretted selling off all their copper...

    1. Christian Berger

      Actually no

      This is a stopgap solution for very short lines, and this, if it will even work in practice, will only work for very short distances and with very complex equipment. You already need high double digit gigabit speeds in the backplane of a vectoring DSLAM, not for the data itself, but for all the data you need to send around to eliminate cross talk.

      On the other hand, once you have a fibre, it's cheap to run 1 Gigabit over it. The lasers and detectors for that costs about 20 Euros per side. For 10 Gigabits that goes up to 50 Euros. Both optics can plug into bog standard Ethernet equipment. And for fibre the limit now actually is how to get the data away from the optics fast enough. So far only 100 Gigabit Ethernet uses QPSK which is about at the level of sophistication needed for 9600 bps modems.

      1. yoganmahew

        Re: Actually no


        And if you have to replace the copper with specially shielded, break free new lines, why would you not go fibre already? (I presume my rat eaten phone line, patched in numerous places would be unsuitable!).

        1. PNGuinn

          Re: Actually no

          But would it work in Milton Keynes? (Ally cables.)

          Seriously, does this waveguide effect require a decent smooth bit of copper?

          What about all the dinks in the conductor caused by crimps and IDC terminals in all those joints?

          Security / crosstalk?


          Sounds a nice idea but I'd like to see some real world test results first.

      2. John Miles 1

        Re: Actually no

        I think 100Gb is a bit more than a 9600b modem - needs optical coherent detectors and dual polarisation, adding DWDM can get one to 10 - 20 Tb per fibre. However the ironic twist is that 40 years ago ( before the first public trial of optical fibre transmission in the UK that achieved 140Gb over 12 miles) the proposed solution for long haul high rate transmission was a waveguide made by lining a tube with copper wire. Plus ca change ...

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  2. Oengus

    Exponential Drop off

    you get to a Terabit system that Cioffi reckons can operate at 100 metres; 100 Gbps at 300 metres; and 10 Gbps at 500 metres

    and at 2500 metres you get ?

    I wonder what the "average" local loop distance is in Australia... and what "quality" of copper you need compared to the existing services.

    1. Christian Berger

      Re: Exponential Drop off

      It's a stopgap solution, designed to run those speeds over short runs of bad copper. The only usecase for this is inhouse cabling on old buildings, where you put a DSLAM in the cellar and bridge the last metres of copper. It's rather idiotic as running fibres will cost _much_ less than such a DSLAM.

    2. Tom 7

      Re: Exponential Drop off

      The annoying thing is the technology is available to make low power gigabit repeaters for a couple of quid that could be cheaply dropped in every couple of Km on copper anyway.

      But then BT had the capability 27 years ago to put in 10km of fibre and have 2.4Gb end to end for an equipment cost less than £100 per line but they 'didnt do research' anymore.

  3. Voland's right hand Silver badge

    Pointless excercise

    Diminishing returns continue.

    Can we just, finally, let it die and put fiber in the ground.

    1. P. Lee

      Re: Pointless excercise

      >Can we just, finally, let it die and put fiber in the ground.

      Is it just the Oz press getting the wrong end of the stick based on DSL being a long(ish) range tech and this is by the same person?

      Surely this is more for "inside-the-data-centre" where the exponential drop-off isn't an issue?

  4. AndrueC Silver badge

    Interesting stuff. I wonder if it fits in with the document that Ofcom published a couple of years ago? I think it was a (very theoretical) review of how far twisted pair could be taken in the future.

  5. Wolfclaw

    TB speeds, until BT/OpenReach/Virgin get their hands on it and you will be lucky to get dial up at daft prices !

  6. Andy The Hat Silver badge

    Magic ...

    It's all smoke and mirrors I tell you. When I were a lad, you needed waveguide for a 1GHz signal, and then they made computery things that ran at 100MHz and didn't swamp Radio 1 with noise - though I admit it was hard to tell the difference ...

  7. Korev Silver badge

    Don't tell BT...

    ...they just use it as an excuse to not lay fibre to the home....

    1. David Webb

      Re: Don't tell BT...

      They tend not to do FTTP anyhow, mostly FTTC. FTTP is a major pain in the arse anyhow, the BT guy comes out and sticks the modem on the wall, then sticks on a battery backup for Fibre Phone which doesn't exist, but they stick the battery on anyhow and then nag at you when the battery backup breaks and they have to come out and replace it. "But you don't need it, so why replace it?" "you stick it in, you replace it if it breaks".

      Then there is the ISP's that support FTTP, is it 4 or 5? And then they only give you FTTC speeds anyhow, the only bonus being you actually get the full fat 80Mb.

      1. Roland6 Silver badge

        Re: Don't tell BT...

        Then there is the ISP's that support FTTP

        I think you will find that the ISP's either require a BT FTTP line, because they are in dispute with Ofcom over who should be supplying the battery backup, specifically they want BT to provide the battery for the FTTP line they installed and for which BT doesn't get any service fee's from, or they expect the house to have the BT POTS over copper service for fixed line telephony (which effectively leaves the power/battery issue with BT but this time BT do get some revenue).

        FTTP is occurring more on recent larger new build developments (ie. developments of 20+ homes built in 2016 and later). I don't know if the cable being used is pure fibre or also has copper cores; it would make sense for it to be pure fibre, but then copper cores can aid fault location and diagnosis.

  8. Chris Evans

    Showing my ignorance probably..

    but I wonder how (When it eventually arrives) the much slower signal that goes down the center of the wire doesn't interfere with the data then being received from the edge?

    1. This post has been deleted by its author

      1. Chris Evans

        Re: Showing my ignorance probably..

        "Why would you still need the slower signal? "

        You don't need it and you don't want it, but wouldn't it be there and interfere with the faster signal. I guess they must have a way of filtering it out.

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        2. This post has been deleted by its author

  9. Kevin McMurtrie Silver badge

    "Energy still leaks off wire if bent"

    Typical telco wires go through several junctions that are one big rat's nest of crushed and untwisted wires. Even with a neighborhood distribution box, there's at least one more junction mess on the poles and a few more in the house. Each tiny disruption to the wire pair is an impedance mismatch, an antenna, and a low pass filter. This is why DSL is slow and this is why telcos can't just send plain old Ethernet down the wires.

    Just replace it already.

  10. Herby

    This of course begs the Question: How much bandwidth do you need at home?

    And as anyone knows, the answer is: More than I have now.

    With all the point to point connections demanding bigger and bigger hoses for the data, consumers have demanded more and more data through inefficient connections. At one time we had "Broadcast" technology which if you summed up how much data was consumed by individuals would get an enormous number (sure it was all the same data, but that is what BROADcast means).

    Now we have all these point to point links between providers and consumers that want anything and everything on an on-demand NOW basis. Satisfying the bandwidth habit will only get more expensive over time as "replace" happens over and over again.

    Sad but most likely true. (*SIGH*)

    1. Tom 7

      Re: This of course begs the Question: How much bandwidth do you need at home?

      It seems to be a zero sum game. At home I have 2Mb which is not enough to watch video over but is more than adequate to browse the web except where people fill page with unnecessary and uncompressed images by the thousand.

      If you take into account what I ignore the real data rate is as fast as I can read most of the time, its just the noise level has gone up since 2400 baud dial up.

      Upgrades can be scheduled to run overnight with minimal effort and caching proxies reduce my bandwidth volumes by the eight or ten machines I'm running regularly. Intelligent downloading of TV is possible - things I miss on BBC are get-iplayered overnight and if tv services did the same for box sets and series I'd guess the average family could live on less than 20Mb - people in my local village who have 70Mb say they never needed the fibre upgrade from 17Mb - apart from one mate who has more video than he can watch in his lifetime already.

  11. joemostowey

    Speed is of the essence, but obscene profits are much nicer.

    Wouldn't matter if it could transmit 100 terabytes over infinite distances, it would never get implemented in the USA as the business model here is to minimize competition, and sell the minimum capacity at the maximum cost. I expect to see the merger of several wireless broadband suppliers in the near future, as T-Mobile has forced the cost of wireless data to slide, messing up AT$T and Verizon's decade long price fixing monopoly. why sell terabyte speed when you can force the end-user into accepting megabyte speed because the end-user has no choice?

    The cable companies have used this model for decades and made very healthy profits, with little innovation, until Google fiber came along (of course, google is now getting out of the business) and forced higher speeds.

    It's ever so much more profitable when you can create an artificial shortage.

    OPEC showed them how it could create a viable, profitable business model based on a perceived shortage, and milk the Rubes for everything they could, all with governments covert approval.

    Terabyte speed? Not gonna happen, over copper, over fiber, or over the air.Just pay your $10.00 per gig and be silent, (and Smile!) you shall be happy to accept our domination!

  12. JaitcH

    One thing for sure, copper with paper insulation and lead sheathing won't cut it!

    There must still be hundreds of miles (even more kilometres) of the former Post Office TelephoneS (POTS) cabling lurking in Great Britain.

    As a new fibre optic subscriber, with proper government regulation with respect to sharing, has to be better than trying to resuscitate an old technology. Apart from this there are environmental and health considerations to be considered these days.

    China, and Indochina, have invested heavily in fibre optics with great success. Cambodia, a circular shaped country, has brought modern services to formerly isolated areas. VietNam, an elongated shaped country has almost all forms of communication using fibre, from TV programming, long-haul cell links between cell sites, etc.

    All services (supports pure data, Data +Voice, Data+ Voice+ WiFi, etc. and can provide up to 1.25Gbps uplink and 2.5Gbps downlink transfer rates) are available. I chose TWO 100Mbs InterNet services from different suppliers emanate from a single modem attached to a single fibre optic.

    The vertical 'house wiring' fibre optic that feeds each floor of 20 apartments, plus five spares, has multi-core feeds all in an external diameter of that of a lead pencil.

    Putting old technology on life support will be for all the wrong reasons - many financial (which don't reduce consumer installation charges).

  13. Anonymous Coward
    Anonymous Coward


    Another excuse for BT to refuse to deprecate their obsolete copper network...

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