back to article ITU suggests replaceable cables for power supplies

The International Telecommunications Union (ITU) has kicked off its Green Standards Week with a proposal for the world to standardise the power supply units (PSUs) provided with devices like mobile phones and laptop computers. One of the standards the ITU proposes would see the ubiquitous devices equipped with replaceable …


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  1. Steve Carr 1

    An awesome idea!

    I have a couple of large boxes of old power supplies, from discarded/broken/obsolete electronics gear. Whenever I find a need for a replacement power supply, or some potential application for a voltage adapter/power brick, I shuffle thru the boxes and see if something there will do the job. This usually entails getting out the soldering iron, and fitting a different tip. Way better to have standardized tails on the units, for sure!

    What we need now is the EU to take the initiative and mandate it.

    Of course there'll always be an worm in the Apple (pun intended) - where a manufacturer insists on a proprietary standard. See the new iPhone for instance......

    1. This post has been deleted by its author

    2. Captain Scarlet Silver badge

      Re: An awesome idea!

      Let me try that again in English.

      O_O how are you able to do that, if I so much as look at a soldering iron the H&S Team start bellowing NOOOO! and order me to fill out a near miss for almost setting fire to something or causing a trip hazard with the short wire.

      Atm I install RAM in a cupboard using torchlight to evade detection (As my prep room was turn into the server cupboard and my nice big server room turned into a meeting room).

  2. Esskay

    Hell. Yes.

    I've half a dozen PSU's kicking around in a big box of cables, which get sorted through when I decide to fire up an old laptop. Cue 10 minutes of connector roulette as each laptop/device has it's own proprietary connector, things would be a hell of a lot more convenient with just a single PSU and a manufacturer-specific cable - as with the above poster, I don't expect *all* manufacturers to enjoy the taste of the ITU's fruit (ahem) but I expect any intelligent consumer will adjust their purchases accordingly.

    Beer for the ITU finally doing something about yet another proprietary mess.

  3. TeeCee Gold badge

    Obvious answer.

    USB. Mandate USB power, power block terminates in a USB A socket, device cable is USB A plug to whatever.

    Quite common already and thus pretty much the de facto standard. All that's required is USB supplies capable of chucking out sufficient oof to satisfy larger devices.

    USB power delivery spec allows up to 100W, which should be enough for phones, tablets and laptops.

    1. mccp

      Re: Obvious answer.

      Unfortunately, probably only obvious if you don't design power supplies.

      At 5 V you need 20 Amps for 100 Watts - which is why laptop supplies are usually around 19 V so that you can use nice thin, flexible cables.

      There's a strong case to have a selection of voltages, say 5 V, 12 V and 20 V to cater for requirements between 10 W, 25 W and 100 W with standardised plugs & sockets. Then you'd probably get the likes of MK building SMPSs into 13 Amp mains power sockets and we could all begin to forget about wall warts.

  4. Anonymous Coward
    Anonymous Coward

    USB power delivery spec allows up to 100W, which should be enough for phones, tablets and laptops


    "The Battery Charging Specification 1.2 of 2010 [12] makes clear, that there are safety limits to the rated current at 5 A coming from USB 2.0. On the other hand several changes are made and limits are increasing including allowing 1.5 A on charging ports for unconfigured devices, allowing high speed communication while having a current up to 1.5 A and allowing a maximum current of 5 A."

    Now at 5v that ain't gonna give you 100watts

  5. Andrew Baines Silver badge

    About time

    Can we do it today please.

  6. Old Hand


    Nice idea; most of us have boxes of Wall-Warts for dead equipment. We are able to wield soldering irons better than many, I expect. Some good work has been done already in adopting figure-8 for input and now we need a standard for DC output cables. But not USB, precisely because it already has a power rating too low to be good. Then what to do about the current rating at each voltage? Mustn't overheat them. ??

    1. Dave Bell

      Re: PSUs

      I have experience of laptops which use a connector carrying several times the current rating that is published for the connector. It was an old machine which I bought cheaply, and it died when the socket failed. It was, in its day, a top-end machine.

      I don't think a USB socket should be the only way of connecting, but a lot of small stuff can re-charge that way. Looking at the ultra-thin computers which need more power, I see ultra-thin co-ax power connectors, and I wonder how they can reliably carry the current. How do they have enough contact area?

      Some sort of flat connector, in the same general style as USB or HDMI, might be the solution. But using a physical USB connector for supplying a non-standard voltage and current is just asking for trouble.

  7. Anonymous Coward
    Anonymous Coward

    USB @ 100W (maybe) vs Power over Ethernet at 25W (maybe 50W)

    There's an overcomplicated 2012 proposal for USB to be extended to provide up to 100W, as reported in various places e.g.

    For 25W or so, which covers a great many things, surely power over Ethernet is tried, tested, proven, and could be cheap as chips? 25W you can do using industry standards, some vendors claim 50W using proprietary extensions but that way lies danger.

  8. Britt Johnston

    re “PSUs areThe main cause of failure'

    More of my personal losses have been due to on/off switches.

    One cause is the useful but philosophically disturbing idea of a PC controlling its own power supply, a power grab that swaps robustness for functionality.

  9. Mr Fuzzy

    While they're at it...

    How about the other end of the connection? It's a sod of a job to sort out a laptop where someone has used the "Wiggle the cable until it works or something crunches," technique and snapped off a jack directly soldered to the main board. Imagine my joy when I got at the guts of my elderly Tosh laptop the other day and found not only that it was on a tail, but also had a pair of redundant wires.

  10. b166er

    This WON'T be popular. Certain laptop vendors I can think of, like selling laptop power supplies with a healthy mark-up.

    I hope it happens however.

    As Mr Fuzzy points out too, sort out the charging port end on the low voltage side. I echo the joyous sentiment of ordering a replacement laptop DC jack and finding that it has a tail and connector rather than requiring soldering. My own idea is that the plugs on laptop power supplies come away from the leads easily. Somewhat like the multi-voltage power supplies you can buy with the 2 small pins making the connection to the plug of choice.

    Then when your hapless victim kicks the low voltage portion of the power supply, the plug is left in the charging port and the lead falls to the floor/

    I suppose magnets could be used for this too, unless someone has patented that idea of course!

    1. Anonymous Coward
      Anonymous Coward


      Apple, strangely enough. Look up the MagSafe connector.

  11. A J Stiles
    Thumb Up

    Another idea

    This is all good, but there's something else we need to think about.

    Why not mandate for PSUs to be housed in screwed-together, rather than glued-together or welded cases?

    This way, if (read: when) the cable fails at the unavoidable concentrated stress point where it exits the housing, the power pack can be opened up, the cable shortened by 10 cm. or so, and then re-soldered to the output. Screw it back together and the job's a good 'un.

    It's called field-maintainability; and it's most of the difference between old-fashioned industrial (and semi-industrial) equipment which is still in use after 20 years or more, and nearly-new equipment which is festering in landfill sites for want of some awkward, piddly component which seems to cost as much as a new one.

    1. Anonymous Coward 15

      Re: Another idea

      Assuming Tom, Dick or Harry could use a soldering iron without hurting anyone or turning the device into a fire hazard and blowing the house fuses.

      1. A J Stiles

        Re: Another idea

        Well, if they do that, it's their problem.

        Those of us who know how to do something properly shouldn't be prevented from trying just because some of us don't know how to do it properly.

        1. Anonymous Coward 15
          Thumb Up

          Re: Another idea


        2. kain preacher

          Re: Another idea

          Lawyers and idiots make for silly thing. Like this warning label on a curling iron. Warning not for internal use. I'm of the opion that if you van not figure out not shove a hot curling iron up you you deserve what ever you get.

    2. davemcwish

      Re: Another idea

      Good idea but wont happened fo two reasons:-

      1. The current environment is to work with the lowest common denominaror of end user i.e. they can't be trusted not to kill themselves so must have sealed units

      2. It's an extra revenue stream for the manufacturers and retailers

      Another complaint I have on powercables is having a moulded plug and too short a cable on my recent washing machine both of which cause installation issues; several minutes with a screwdriver, a longer length of 3 core flex and a new plug fixed that.

    3. Anonymous Coward
      Anonymous Coward

      Re: Another idea

      "This is all good."

      Actually, it's not. Like many posters I've got a stash of surplus power supplies, and that's because the damned things are on average more durable than the equipment they are designed for. Rather than working to over-engineer PSU's because a few fail, the ITU might care to think about the short service life of some technology kit.

      1. A J Stiles

        Re: Another idea

        The problem isn't so much that PSUs are over-engineered, it's that the appliances they are supposed to power are under-engineered.

        Any field-maintainability directive would, hopefully, extend as far as actual appliances .....

    4. Charles 9 Silver badge

      Re: Another idea

      That's assuming the failure occurs at the brick. Mine tend to fail most often in the middle, where some consistent kink eventually breaks a wire open.

  12. Ellis Birt 1

    With EU support, this could be a runner.

    Careful design of the DC output connector would be required to support different voltages, single and double-ended, maybe communicate the required voltage and current limit to the brick.

    A new market in universal power supplies could be born, devices shipping with just the cable. One 8-way brick on the charging table at home, portable single-way for mobile use, power out socket in you car...

  13. DanceMan
    Thumb Up

    Great idea, overdue

    Wouldn't mind if they outlawed chassis-mounted connectors while they were at it -- another common failure point on laptops and tv's, in my experience.

    1. Anonymous Coward
      Anonymous Coward

      Re: Great idea, overdue

      Chassis-mounted > PCB-mounted.

    2. cortland

      Re: Great idea, overdue

      Chassis mounted connectors are needed, if only for ruggedness and shielding termination (where shielded cable is used). Connectors mounted to a PWB break, if great care is not taken inserting and removing them, and if the equipment doesn't fall from the table or someone trip over its cable. When the connector is mounted to the chassis, the energy of those events is distributed across the whole assembly, possibly allowing it to survive. Which is a good idea!

  14. Ole Juul

    I like binding posts

    One red, one black.

  15. Fuzz

    forget the itu

    This needs to be mandated by the EU.

    there's no need for all the different voltages we have now just have 2 or 3. Small devices like phones, cameras and tablets can use 5V which can be supplied via a USB plug. Larger devices like laptops can use 19V with a large coax connector. If a large coax connector isn't the best design make something flat but make sure it fits in both ways round. Maybe have a middle voltage like 12V for routers, battery chargers and anything else.

    Make all cables detachable, make all PSUs sold meet strict efficiency requirements. Make the PSUs universal, sell them as single, dual or tri voltage. Tri voltage PSUs can do all 3 voltages, single can just do 5V. For the multi voltage PSUs make them able to automatically choose the correct voltage based on the attached cable.

    1. Anonymous Coward
      Anonymous Coward

      Re: forget the itu

      "This needs to be mandated by the EU."

      Well, there's no more pressing problems for them to sort out at the moment are there?

  16. Andy The Hat Silver badge
    Thumb Down

    Yep, great idea in theory, never work in practice ...

    Need standard connector at the psu ... how many terminals? What about multiple voltages, sense cables and the like? Not impassable but an issue.

    Need standardised plug at the other end ... hmm laptop has markedly different requirement to hub or a big switch or Jimmy's fire truck, or Dad's 2.5M candlepower torch ... so it's not ideal but let's say it could be done ...

    Need standardised lead in between ... now this gets awkward, 0.1A, 0.2A, 0.5A, 1A, 2A, 5A ... with however many power rails each at the correct current rating for whichever device ... you could end up with a massive rack of terminations rather than power blocks and not really save anything ...

    1. Anonymous Coward 15

      Programmable SMPS

      and a 1-Wire chip in the device?

  17. nichobe

    what about tablets

    The ITU and EU should force a standard plug and socket for tablets also!

  18. This post has been deleted by its author

  19. Gordon 11

    We' had EU standads for mobiles...

    Unless you are Apple, in which case

    * All connectors have to be at least 25% smaller than the standard

    * They can only have one prong.

  20. Kernel

    "But using a physical USB connector for supplying a non-standard voltage and current is just asking for trouble."

    Not really - the PSU supplied with the Asus Transformer range of tablets has a USB 3 socket on the wall wart - if it detects a Transformer it supplies 15V, fails to detect a Transformer the same socket supplies 5V.

    The only trap for young players is that if you want to insert a USB extension lead in the middle it needs to be a USB 3 cable to support the Transformer detection process, otherwise you just get 5V out.

  21. cortland

    Loupes, loops, and RF noise

    All part of sensible product design. For many years -- a couple of dozen, anyway -- leading Japanese Amateur Radio makers used the same 6-pin power connectors for HF radio transceivers..Granted, "wall warts" don't have to deliver 25 Amperes, it'd be d*mned useful not to need a jewelers loupe* to see what polarity and voltage thw PS label shows. *(And how about letters more than 0.3mm tall?)

    I'd insist, however, with efficiency standards now pretty much mandating switch-mode power supplies, that RF emission (>9 KHz) be kept well below the EN 55022 and FCC Part 15 limits; what is the sense of a power supply that renders a radio it powers (and others nearby) unable to hear radio stations?

    For examples of testing, limits and design tips see

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