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New USB Specification Promises 100W of Power
Blacklaw writes "The group behind the USB 3.0 specification has announced a tweak which could lead to impressive new devices, including large-format displays, printers, and even laptops that are powered entirely from a USB port."
Awesome. I'll finally be able to implement those high powered "negative reinforcement" keyboards I keep dreaming about.
and display port is better and put's the load on the video chips / gpu. Maybe use usb for power and not data.
Netbook battery life drops to an average of 12 minutes.
Burns: We're building a casino!
McAllister: Arrr. Give me 5 minutes.
Taking bets on how long before a USB powered vacuum cleaner comes out of Asia!
> laptops that are powered entirely from a USB port Finally I get to plug 2 laptops together whir their USB ports. Free perpetual energy. Problem science ?
So where is the power coming from a AC to usb power only box?
Why not just keep what they have now? works in more places. Also some kind of standard car power jack in put will be nice to for laptops.
So now, I can hook my computer to my car to jump-start it!
You know? Long ago, Apple made a display that was powered through the display cable. It worked but it was not popular in the end as they stopped doing it. So they are talking about bringing it back again?
I can see power enough to power some devices, but 100W?
You know, whatever USB standards come out, it should work equally well on a battery powered laptop and a desktop as well. People will get confused and frustrated when they buy a fancy new USB 3.0 display unit only to find they can't take it with them on the road because it doesn't work well with their laptop and the tiny travel power adapter they use while on the road.
I was hoping Power over Ethernet (PoE) was going to be successful since it would mean a LOT less cables, but this seems like a good alternative. I just hope it becomes a standard because PoE was nowhere to be found.
USB 3.0 should be less CPU intensive, because IIRC they switched from a polling protocol to an interrupt based protocol.
Who cares? If they get to the point that they can show HD video over USB 3.0 without sending all the CPU cores to 100%, then that's a win. I use a USB 2.0 / VGA adapter to increase my Work Notebook from 2 screens to 3. The USB one is usually just showing a datasheet PDF, schematic, or some other static display. Fantastic increase in capability for $50. The USB adapters have have their place, just like mobo-integrated graphics and $300 discrete cards have their place. The exciting thing is the possiblity of integrating this directly into a monitor. Have a sudden need for 6 monitors to display different power point displays at a convention? Just plug all 6 into a USB 3.0 hub attached to your notebook. That's awesome stuff. It won't replace HDMI or display port, but again, great additional functionality.
What else has driven technology so hard? Pun intended.
... well, shit. Designing a motherboard to handle such power is relatively easy and can be done cheap, but there are ton of PSUs out there, even in OEM PCs, such as HP, Dell, Emachine, etc. that are average at best in terms of quality and cannot output their designated wattage and they are usually 300-400watt maximum output.
The big PC manufacturers will have to be able to have PSUs, even in the low-end models, to handle that extra wattage capability. I've seen a ton of OEM PSUs go bad after regular use.
Previewing comments are for sissies!
about using the heat form the pc to heat rooms?
are we approaching a world where we can replace our electric outlets and our heating ducts with our pcs?
when can i replace the sump pump and hot water tank in my basement with my pc?
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Does this mean that USB3 cannot be implemented on tablets, netbooks and other low power portables?
Good news in my book. Now they need to provide USB mode for transferring data over hundreds of meters long cables, as last remaining (Ethernet) obstacle towards unification.
839*929
The current spec allows for about 4.5W (900mA at 5V). One of the last sentences in the article mentions 0.9 Watts.
Now, I could totally understand this kind of mistake in the past. But don't these people understand the wonder that is Google? Before I made this post, I wanted to make sure that I wasn't the dufus, and typed 900mA * 5V into Google. It's not that hard to fact check, is it?
"I will trust Google to 'do no evil' until the founders no longer run it." Hello Alphabet.
Imagine a voltage of 5 V, to draw 100 Watts from that you need a current of 20 Amperes. The german DIN 57100 requires a cable of 4mm to provides such a current.
Voltages inside a PC are usally 5V and 12 V. For 12 V you still need sort of 8,333 Amperes, that means 1mm for the cables. The other problem will be the plugs and sockets. 20 A is enough to sort of solder the contacts together or start a small fire if there is too little contact between them. Ok, lets imagine a device that can negotiate 100 Volts, then you just need 1 Amperes for 100 Watts. Fine, but that means that the USB connection now needs to be treated like a healt hazard because its over 65 Volts and can proivde more then 50 mA.
I'm really curious to see how they will jump over that physical obstacle. :-)
My laptop has a 65W power adapter.
If the USB ports are rated for 100W, I would need a 365W power adapter(3 USB ports), and a battery capable of discharging at the higher rates.
So, would only people who can easily carry 10+ kg with them all the time have laptops?
900ma at 5V, using a standard power(W) = Current(I) time Voltage (V) w=iv. 900ma = .9A *5V = 4.5W
Powered USB is essentially a USB connector stacked with a seperate power connector. This makes the port more than twice as tall which afaict prevents it being placed on a standard expansion slot backplate and considerablly reduces the number of ports you can put on say an ATX backplate. Worse there are three voltage variants which are all incompatible with each other.
The result of these defeciancies is that it has only found niche appeal.
note: i'm known as plugwash most places but i screwd up registering that here somehow in the past and now can't register
you liberals and your fancy pants words and regulations.
we need 1000 watt USB ports, then we can run a BBQ grill and piss off the vegetarians
Thanks - very informative. I thought there has to be something like that now USB is so widely used.
Once again, USB starts out way behind the game. Last time it still overtook Firewire and buried it. But I have a feeling that this time, with Apple in a completely different market position, it's not going to be so simple to catch up with Thunderbolt.
all chinese power supplies are 100% best quality. it says so right on the big box they ship it over in.
why would they lie? the people's interest are automatically represented by the party representatives. why would the government ever allow a shoddy product to be shipped overseas?
it just doesnt make logical sense.
and never hacked.
it reminds me of the PC days of the 80s, when a DOS virus could overdrive the monitor controls and shower the user with Xrays.
Even with USB2, there was the persistent problem that certain applications(notably 2.5 inch external drives) were right on the edge of what the spec allowed. Some machines played fast and loose, and everything worked fine, some played to spec, and the device wouldn't spin up, or the bus would freak out, or whatever. Despite USB's formalized, standardized, power-request mechanism(100ma on connect, negotiate in units of 100ma for up to 400 more...), the, er... 'inventive'... nature of the peripheral ecosystem always created some uncertainty: Some devices just requested 500ma at all times, to avoid possible brownouts, leading to more spec-compliant busses freaking out about lack of power even when actual draw was well within safe limits, some devices (fans, LED goosenecks, humping dogs) just grabbed the +5 and ground rails and hoped for the best, without any negotiations. Some hubs report themselves as self-powered(and thus good for 500ma per-port) even when they were bus powered(and thus only good for 400ma across however many ports they had). Some others were self-powered; but with wall-warts that could only deliver 500ma to a number of ports smaller than the number available(7-port hubs with 1amp adapters, I'm looking at you...)
This new standard seems like it would simply be a polite codification of this confusion. Particularly at low voltage, 100watts is nontrivial current(and nontrivial power generally, most non-DTR laptop bricks are less than that...) Many PCB layouts would burn a trace trying to deliver that, and you can bet that your garden-variety 10-USB-ports boring desktop isn't going to ship with 1000watts of PSU headroom...
This will mean that, in effect, devices will be able to demand up to 100 watts in a 'compliant' way; but the capabilities of USB ports on the market will vary enormously by device. A laptop with an 85 watt power brick is hardly going to be good for 100watts out of a port. Worse, it might be good for 50 when lightly loaded and fully charged; but only 5 when charging its battery and flogging its CPU... Having a device that only intermittently functions is near worthless, even if it is all entirely standard... A desktop might ship with the ability to push a single port to 100; but then it will either have to beef up its traces significantly, or have the always-confusing-to-dumb-users-and-people-fumbling-behind-desks '1 special blessed "high power" port, and 9 identical-feeling-but-low-power ones' configuration. Fan-fucking-tastic...
While a bit more power on the bus certainly would expand the number of viable, bus-powered use cases, I'm just not sure that such a high 'standard' number can ever be usefully 'standard'. Hooray, it is now officially standard for specialized devices to shove 100watts across a USB bus. Doesn't change the fact that it won't work in 90+% of ports, and will probably burn a fair percentage of cheaper cables. Unless they come up with some sensible set of "tiers", so that people actually know what works with what, this seems like it is going to end in a mess of nominally-USB powered docking stations with wall warts and mini-B connectors, at best.
While its comparative obscurity, and the general lack of bus-powered devices made it less of an issue, Firewire flirted with this problem in its early days: Both available power and available voltage on a given 6-pin port were widely variable: A desktop could, if it so chose, be pumping out 24 volts and reasonably credible wattage. One of the(almost exclusively Apple) laptops with a 6-pin port might be limited to a handful of watts at whatever voltage its battery was set to provide. In practice, much firewire gear just skipped bus power entirely(despite the fact that charging over firewire would have been a very popular consumer camcorder feature, if today's flip-likes are anything to go by), the mixture of widely variable power availability, and the 'i.link' or just 'IEEE1394' connectors entirely without bus power pretty much doomed the widespread availability of bus-powered peripherals. USB's pitiful 2.5watts was rather limiting; but at least you could reasonably assume that it would be there...
I'm looking forward to the USB-powered space heaters that office secretaries will put under their desks. They were forbidden from doing that before because it takes too much power from the wall plugs, but this comes from the COMPUTER so it must be okay!
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
At higher speeds the OS stuff starts going back to polling to be less CPU intensive :).
http://en.wikipedia.org/wiki/New_API
Finally I see a purpose for the 1.2Kilowatt PC power supplies.
One hundred watts per port? That's insane! I could run a nicely-equipped Atom ITX MB, HD, DVD drive, and ION graphics adapter off such a port!
I see USB hubs getting much more expensive if this standard gains traction...
Ken
I wonder if they are hoping to get these new super-power USB ports classified as Electric Vehicle charging stations, thus eligible for several thousand dollars in federal subsidies and grants? Imagine charging your Chevy Volt from your laptop USB port!
Ken
The IBM patent(Umm, a patent for putting a USB jack and 2 DC pins in the same connector?) probably doesn't help...
From the beginning that sucker was basically just a nominally-not-quite-proprietary connector for IBM and partner POS system peripherals. Now that you need an IBM patent license...
My major pet hate with USB. Other than the shitty nature of being entirely CPU driven.
I run: Windows, OS X, Linux, FreeBSD. Just because you have a hammer, doesn't mean everything is a nail.
I don't know how this would ever work on a laptop, or what this will mean for power supplies (probably have to double in size to realistically even use just a small percentage of your USB ports) but the ability to not plug in printers/other high power peripherals to the wall would be nice.
Troll is not a replacement for I disagree.
USB is not really CPU-intensive. The host chip does most of the hard work.
A successful API design takes a mixture of software design and pedagogy.
USB negotiates power requirements. It could refuse to deliver such a high power output. Additionally, it could accept power over usb from a powered hub or whatnot.
9 AWG wire is rated at 19A. 10AWG wire is rated at 24A (http://www.powerstream.com/Wire_Size.htm). That's some serious cabling. I don't think they've thought this thru.
Niche: you mean possibly millions of POS systems :)
A successful API design takes a mixture of software design and pedagogy.
Hey, at least it IS keyed so you can't mess it up.
I don't see it as much of a problem, to be honest (and Mini-USB fixed it). Most USB devices have the USB logo on the top part of the USB adaptor. More stupid are those manufacturer's that fit USB sockets upside-down in their computers.
It's like complaining that the PS/2 adaptor were round and could be put in any orientation (I have sat with paperclip and straightened god-knows-how-many PS/2 device's connector pins)... yeah, if you don't bother to check the pins, or the big "this way up" indicator on them.
this is stupid. There are explicitly reasons to not want to put the load on the video chips/gpu. Part of that is of course, things that don't involve graphics. Really are you that shortsighted? What the hell does a printer need a gpu for? Printers need a CPU to process the data, mostly.
Hopefully they'd design several new "standard" plugs too.
True, but misleading. USB1.0 does nothing less than USB2.0 in that respect.
A successful API design takes a mixture of software design and pedagogy.
And charge the netbook from itself!
I'm really looking forward to the required power supply that will be the approximate size and weight of a cinder block.
Moot issue. USB3 is going to be about as ubiquitous as Firewire800. USB2 hits all necessary expectations for its pricepoint, and Firewire400, eSATA, or good ole ethernet cover everything USB2 lacks. They'll get a slight bump from being new, then it's all yawns.
War as we knew it was obsolete
Nothing could beat complete denial
- Emily Haines
So you don't think it'd be nice to just have a single connector on your mobile phone/tablet that did everything from charging it to connecting to a display?
Want to connect up you mobile to the TV to show the vidoe clip you recorded: use USB.
Want to print from your tablet: use USB
Want to take the video clip from your mobile to edit it on your tablet: USB
Want to charge your device while it is connected to printer or TV,: USB
It is after all supposed to be a Universal connection standard, if we can use it for everything, then then surely this is a good thing?
"The weirdest thing about a mind, is that every answer that you find, is the basis of a brand new cliche" -
Except this isn't USB 3.0 - 3.0 version 1.0 (yes, it is called 3.0v1 in documentation) is out the door and in devices from several manufacturers already. Since they made careful note that it is version 1.0 of the 3.0 specification, this upcoming version could be anything from 3.0v2 or 3.1 or even 4.0 - whatever their product marketing elves decide. As for whether it is less CPU intensive or not, you've got me. I also haven't heard anything about polling vs interrupt, but it is backward compatible with 2.0 (you need special 3.0 cables to use a 3.0 device), so if they did make such a switch it probably has to support both. The one thing I had heard is it is full duplex now. Oh, and Intel is holding back support at the moment (rumor has it to promote Thunderbolt, which they co-developed with Apple), but board manufacture MSI has one (in fact, I just built a computer with one, and apparently I got lucky on the crap shoot with that board because they seem to have an extremely high failure rate - mine works perfectly... makes me wonder if there is a BIOS issue [like memory timings specced too high for the cheap memory people tend to buy - I've actually had that problem on an ASUS board and it looked like the board was DOA]), and I think AMD has some as well.
Wake me up when USB can deliver 1.21 jiggawatts.
alias sudo="echo make it yourself #" ; # https://pipedot.org/~stderr & http://soylentnews.org/~stderr
On decent chipsets it isn't: the hardware handles the polling then generates a linked list of data fetched from the devices for the CPU to process at its leisure. Likewise any data the CPU wants to send it packages up into a linked list for the hardware to schedule out next timeslice.
"The weirdest thing about a mind, is that every answer that you find, is the basis of a brand new cliche" -
Actually one of the main use cases for this would be charging tablet computers. The tablet would have a single connector and negotiate to never supply power above that required for base peripherals. However it would negotiate to accept as much power as the peripheral will give it.
This would mean that you could plug your webcam into your tablet and it would power the webcam, but when you had the tablet plugged into your TV in your lounge then it would charge from the TV (whilst the tablet was providing the display for the TV).
"The weirdest thing about a mind, is that every answer that you find, is the basis of a brand new cliche" -
Unless they will change the connector, it will be a mess. The current cables can not possibly deliver 100 watts of power, they're too thin... at best they probably an do about 30 watts.
People will use cheap cables with thin wires to power a printer that needs 40-60 watts of power and will find themselves with burnt cables or even worse, usb ports on the motherboards dead (the individual fuses blown up)
Also, power supplies at this time use separate circuits to deliver up to 3A to the USB ports even when the system is down - this is useful to have wake on key/mouse/modem capability and also to charge devices through USB ports. It's done this way for efficiency.
I don't know how they plan to keep this with the new standard - having ports that can't do high wattage and ports that can do on the back side of the computer would only confuse people.
And last, it's not unusual to have 6-8 USB 2.0 ports on the back of a motherboard - I just can't see how the metal traces on the motherboard could possibly support 100 watts of power to EACH connector... not to mention the metal traces and the whole area will warm up even more due to the high current flowing there, and there's already the cpu voltage regulation system there.
You have too the risk of arcing on the connectors (ahhh the smell of melting connectors and burning cables) when you put many amperes on a small cooper contact.
Religion: The greatest weapon of mass destruction of all time
That's still typical sucky microcomputer architecture, shame the designers of our wintel boxes haven't learned a damn thing from the superior architectures of decades past. Past time we had some real PPU. The CPU involvement for the data transfers should be almost zero.
Just plug all 6 into a USB 3.0 hub attached to your notebook.
Problem becomes the bandwidth of the bus. You hit up against this wall in USB2 if you try to .. say.. hook up 4 web cams to a computers onboard USB. I imagine we'll see the same problem with USB3 and notebooks. The amount of shared bandwidth will limit how much you can do.
Sounds like you'd need two connectors
One for connecting the device to something (like a computer/charger) .. and one for connecting something to the device (extra display, printer, whatever).
That is unless USB3 can do both?
As several people have pointed out, 100W seems like too much. I bet this is just a specification tweak to provide headroom for devices that need more than 4.5W (like 8W or 10W or 15W). In other words, the spec is no longer an artificial limit on how much power you can provide.
Visit the
Firewire
Lisa, in this house, we obey the laws of THERMODYNAMICS!!!!
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
I'm thinking of attaching my friggin' laser mouse onto a sharks head when USB3 comes out.
"That's the way to do it" - Punch
100 watts is allot of juice. Seeing how the maximum voltage available from a PC power supply is 12 volts I think that we can safely assume that we need connectors rated for 9 amps. Given the size of the usb connector I doubt we can easily get 9 amps to flow as the pins don't have a great mechanical connection. Also to consider, the cables must have conductors of at least 18 awg for the power pair. I forsee the possibility of a pin and sleeve type connector or a new USB connector that is rated to carry the 8+ amps. I also suspect that the 100W is the maximum for all devices on the bus. I cant see having four 100W loads connected to one motherboard, the traces would have to carry over 30 amps and power regulation circuitry would be a board space hog. I can see that we might also need a dedicated molex connector for the USB power supply circuitry unless it can also draw from the 4 pin ATX 12v aux power supply. I bet we will see USB hubs that have 120V going right into them with beefy 12V power supplies to give you multiple 100W ports.
My take? FINALLY! I cant wait to toss those fucking wall warts that are needed for external hard disks. Cleaning up the cable clutter is a big plus. Plus little DIY kits like Arduino can get more juice for bigger projects like motor control. This is nothing but good.
I do agree, and I see this to be a good thing. To use displayport for that is not a good idea. I'd rather use something not apple owned. Nothing about video chip/gpu load requires it to be (or not be) usb3.
very high powered, surprisingly warm to the touch port and unnervingly hot cable respectively powering a printer from a laptop with a curiously malodorous and slightly swollen battery..
Good people go to bed earlier.
Oooh you mean those same ones that pump 24v DC current out of RJ-45 connectors? (that are actually serial...)
Someone needs to get stabbed over that one...
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
I will now be able to charge the batteries on my hybrid with the next gen cell phone. Whew, that'll be a load offuh the grid.
I've seen plenty of high-power USB on POS systems in the U.S. Sure, there are serial links there, too.
A successful API design takes a mixture of software design and pedagogy.
With 127 units (supported by the standard) I could build me a Taser, or maybe even a USB driven electric chair.
My 1000W PSU is looking good right about now.
It's still overly complicated. I recently spent a lot of time working on EHCI drivers for an embedded platform. xHCI which is used for USB 3.0 is an improvement. Most USB implementations use EHCI and OHCI/UHCI. To the host it looks like two separate PCI devices with completely different drivers that must hand-off to one another. OHCI or UHCI is used for USB 1.X and EHCI for 2.0. xHCI also replaces EHCI and OHCI.
At least for EHCI the descriptors are overly complex and 64-bit addressing support is a bit of a hacked on extension.
This post is encrypted twice with ROT-13. Documenting or attempting to crack this encryption is illegal.
Hook up 2 or 3 of these 100W devices and you'll destroy almost any power supply... Very dangerous for the average mass produced computer that only has a few watts to spare.
Probably the PSU specification shenanigans don't exactly help either. Where you have various brands of PSU basically lying through their teeth as to what exactly their PSU is capable of and what tolerances they have. Seriously probably one of the loosest regulated or controlled components, that no one knows about or pays any attention to, and as a result I would say MOST companies as a rule regularly fib about their hardware. I am sure this has an effect on how "true" the USB standard (insofar as supplying a stable constant amount of power) is held up from PC to PC and device to device.
But you are right those 2.5" portable external drives are the worst culprit.
What is interesting to me, is if they get the transfer speeds up enough along with the power, we could start seeing truly modular computers. Need a video card? Plug it in. Need some more CPU cores? Plug it in. Monitor? HD? Audio? Etc... Of course this will lead to an even more messy spaghetti mess of cables, but still an interesting notion.
Saying, "100 W of power" is redundant.
"It is after all supposed to be a Universal connection standard..."
Standard as in a NEW USB 3.0 standard, and not the current/existing USB 3.0 standard? That the "standard" we're talking about...
Odd that they're upgrading the "standard" after Intel upgraded the power output on Thunderbolt.
Any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so.
How about Intel-owned???
Any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so.
well, no. Not tablets anyway. Tablets are a fad, and they are going away.
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
It's a little bit of both. You don't see it so much on PCs since they're so powerful, but it's more evident on smaller embedded devices. The USB itself has some problems but much worse are the host controller chips such as EHCI which constantly polls the bus looking to see if any data structures have changed. If the bus is shared with other devices the slowdown can be very noticeable. I would see noticeable slowdowns just by plugging in more USB devices. Found some fixes by changing bus arbiter and setting latencies. I'm still amazed at the hardware attitude of offloading basic register storage onto the host computer, it's a very PCish design (ie, badly thought out and initiated by IBM).
The basic USB itself needed a bit of shielding because even _idle_ and _unused_ devices or hub chips create some noise due to constant polling, and USB traces on circuit boards can cause problems in some noise sensitive applications.
With 100W of power, the damned plug in device could have it's own GPU, just send it the render data rather than the entire video stream.
It is no longer uncommon to be uncommon.
USB 2: 480 Mb/sec theoretical, real world half that
USB 3: 5 Gb/sec theoretical, real world about 3.2 Gb/sec
DVI: 4 Gb/sec single link, need dual-link for more than 1900x1200 resolution
DisplayPort: 1.6 to 5.4 Gb/sec per lane, four lanes, for 17.3 Gb/sec max, real world is 80% of that (enough for four 1080p60 displays), plus a 1 Mb/sec auxiliary channel.
Thunderbolt: 20 Gb/sec bi-directional, can carry the four lanes of DisplayPort data with room to spare.
So you have less bandwidth than a single-link DVI and far less than the modern competition. Your monitors had better be low-res, even for USB 3.
yeah, I know. Not much better, but at least it works on a wider array of stuff and doesnt' require DRM to function.
Of course not. A USB device must start at low power (1 unit load, 0.2W) and wait for a signal that it can transition to its maximum power draw (5 units - 2.5W with USB 2.0, 6 units - 4.5W in a special USB 3.0 mode). If a lower-power hub can't supply the power (such as a small netbook running off its battery), then attached devices should never transition to high power consumption, which may mean they won't work. I assume this new spec will go further and let the USB hub indicate how much power it can supply in case it can e.g. supply 10W but not 100W.
This is all complicated by unpowered USB port extenders, the dumb battery charging extension, the USB 3.0 higher power mode, and all the USB gizmos and dumb USB chargers out there that don't implement USB correctly. http://en.wikipedia.org/wiki/USB#Power It's amazing USB works at all.
=S
It more likely means that no device will ever draw anywhere close to 100W. Laptops are far more common in the consumer market, and draw something like 20W typically (maybe 50 W under load). I highly doubt manufacturers will beef up the power supplies until such high demand peripherals exist, and such peripherals won't exist until laptops can power them. Classic chicken-and-egg scenario. Plus a lot of people like to keep their printer unplugged from the laptop until they need it, which would be cumbersome if you then have to connect an AC adapter to the laptop.
It's an extension of PCI Express plus DisplayPort over cable. The protocol you run over Thunderbolt may have its own real-world slowdowns, but it's 20 Gb/sec bidirectional as far as I know.
Actually, there is a fair chance that you've got such a device on your desktop computer. If your keyboard has a detachable lead and is an AT or ATX (or PS/2) connector rather than USB, then there's a fair chance that the lead is connected to the keyboard chassis by ... an RJ-11. Which is carrying ... serial data. Even if the keyboard is an AT one (DIN-5 connector on the motherboard end) it's still a serial device.
24V on a serial line ... of course. What's unexpected about that? Read the spec for the commonest (not the only, the commonest) serial standard, RS-232, and you'll see that open circuit voltages of up to 25V are allowed. So, if you're designing anything new to do any sort of serial interfacing, then make damned good and sure to protect your inputs to at least that sort of level. (Look in your IC supply catalogues - you'll find line conditioner chips to that spec in a variety of widths, for precisely this purpose.)
Why big voltages tolerances like that?
Have you ever tried running data to a terminal in a service room with 3x1kVx1kA DC random-activity motor on one side, and two on the other, with the only access that doesn't go past the big motors and their big induced voltages involving rigging the cable over a 40m drop into dark lethal sea? and you've got to rig up, do your job and rig down again in 5 days during a storm when you can't get lifeboat cover? NOW you know that the demands of signal transmission in a warm dry office are not terribly demanding, and that is why USB isn't undisputed king.
I could play the "installed base" card too. The amount of important equipment out there that speaks low rate serial data is substantial. And if it isn't going to replaced in the next 20-year budget, you're going to meet it one day.
You'll learn. Maybe.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
No, someone needs to be stabbed over sending DC power over such a serial link using an RJ45, because I've seen plenty of devices get fried by that, supporting the POS POS-es that use just such an arrangement. Ignoring that, it's still silly to use such a connector, because it's so easy to short (the pins are too close and it's too easy to get something conductive to bridge them).
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
People have been successfully using this sort of equipment for longer than I've been alive.
I've sucessfully used this sort of equipment on a number of occasions after having been told precisely "there were never any manuals ; figure it out yourself ; multi-meter is over there".
The equipment isn't a problem.
So, if the equipment isn't a problem, and the presence or absence of a manual isn't a problem ... perhaps the problem is in the skill set of the technicians or end-users doing the installations. Since you've identified a problem, and you have worked out the ultimate cause of the problem, then you can deliver your manager an estimate of the cost of this documentation/ training failure and an estimate of the costs of rectifying this. Or of not rectifying this.
Ball is in your court. Train your people better (which means that you WTFM(*) yourself, because you seem to understand the issue). Or replace the equipment with something else. Or live with the costs. Give your supervisor the information to make an informed rational management decision (ha!) on the matter.
I hated installing those cables. But once I understood the problem, looked at the alternatives, did the sums ... and got on with doing the job because it was the lowest cost solution, while WTFM.
It could have been worse - the customers might have wanted the colour display, which involved 4 cables, which had to take the shortest route (over the sea) in armoured quad-coax, and which was IIRC £60/day more expensive. "Fun" is not an appropriate word.
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(*) WTFM : Write TFM so others can RTFM.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
I don't think you understand the userbase here.
It's a point of sale, usually manned by bottom-of-the-barrel folks. They think anything that resembles an RJ45 is a "phone plug", and before you even get the call that their barcode scanner isn't working they've already gone and plugged anything that can into everything else. The magic smoke has already been released.
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
Train your people better (which means that you WTFM(*) yourself, because you seem to understand the issue). Or replace the equipment with something else. Or live with the costs.
Deciding it's cheaper to live with a suboptimal situation (e.g. one where accidently mixing up the serial and ethernet lines can fry stuff) than to fix it doesn't preclude hating those who got you into the situation in the first place.
Though IMO the real issue is with the ethernet gear rather than the serial gear. They decided to use the same connectors as phone systems yet afaict they didn't require ethernet equipment to survive connection to a phone line.
note: i'm known as plugwash most places but i screwd up registering that here somehow in the past and now can't register
You're already doing the cost-benefit analysis.
Bottom of the barrel staff are cheap. Add the cost of (say) 2.5 fried bar code scanners per barrel-scraping per year, plus the wasted time (the barrel-scraping's time ; your time ; the POS-out-of-service time) to the cost of the barrel-scrapings. Then compare it to the cost of you writing appropriate manuals, the company training X people per store/ city/ state/ hemisphere/ whatever to do the installations properly ...
I'm sorry, did you just morph into being a cross between Cost Accountant and Human Remains Mangler? Well that's one way into management. Enjoy the descent, because you're not going to come back uponce you start on that slippery slope.
Good luck, BTW, in changing that system for one that suits your design ethic better. You are already in a business where quantity is far more important than quality, so if you're worrying about quality issues like this, then you're probably in the wrong business (for you).
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
Fair point - I'd forgotten that RJ-45s were originally phone equpment, at least in some other countries. I can't think of having seen one on a phone that wasn't an IP phone ... nope ; still can't. But I can remember seeing RJ-11s on American vessels, which caused no end of trouble, in both directions.
So, I guess RJ-45s were for esoteric things like multiple line telephones, or receptionist's mini-switchboards?
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"