USB "Condom" Allows You To Practice Safe Charging

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USB "Condom" Allows You To Practice Safe Charging

Posted by samzenpus on Sunday September 15, 2013 @06:01PM from the plugging-it-in dept.

MojoKid writes "Yep, a USB condom. That term is mostly a dose of marketing brilliance, which is to say that grabs your attention while also serving as an apt description of the product. A little company called int3.cc has developed a product—a USB condom—that blocks the data pins in your USB device while leaving the power pins free. Thus, any time you need to plug a device such as a smartphones into a USB port to charge it—let's say at a public charging kiosk or a coworker's computer--you don't have to worry about compromising any data or contracting some nasty malware. It's one of those simple solutions that seems so obvious once someone came up with it."

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*yawn* these have around for years? by PhrostyMcByte · 2013-09-15 18:06 · Score: 5, Interesting

My MP3 player, the nearly 10 years old Cowon D2, actually came with a power-only USB cable. Maybe their goal was to save money on copper.
1. Re:*yawn* these have around for years? by tjohns · 2013-09-15 18:36 · Score: 5, Interesting
  
  If you plug your power-only USB cable into a modern charger, you'll find that your phone charges quite a bit slower than you'd expect. Modern chargers use the data pins to negotiate whether a charger supports higher currents.
  You don't want a phone to try drawing 2A from a charger that's only designed for 500mA.
2. Re:*yawn* these have around for years? by aXis100 · 2013-09-15 18:41 · Score: 5, Insightful
  
  "Negotiate" is a loose term - really it's just some fixed resistances across the data pins that set USB charging mode. This can be built into the plug without any extra copper in the cable.
  That said for the portable device on the other end to recognise charging mode it also needs to see some fixed resistance, which would need to be build into the far end plug too.
3. Re:*yawn* these have around for years? by viperidaenz · 2013-09-15 19:04 · Score: 5, Insightful
  
  and if you don't connect the data pins, the port, if it obeys the USB standards strictly, may shut down if more than 100ma is drawn without negotiation.
4. Re:*yawn* these have around for years? by 3247 · 2013-09-15 19:45 · Score: 4, Informative
  
  "Negotiate" is a loose term - really it's just some fixed resistances across the data pins that set USB charging mode. This can be built into the plug without any extra copper in the cable.
  For dump power supplies, it's "just some fixed resistances" between data pins. That's a shortcut for chargers that don't want to implement the USB protocol.
  Computers, however, do use the data lines for the intended purpose. With computers, the amount of power that can be drawn is negotiated between the computer and the devices.
  
  --
  Claus
5. Re:*yawn* these have around for years? by SuricouRaven · 2013-09-15 20:31 · Score: 4, Informative
  
  Depends upon device/manufacturer. Some use fixed-resistance, but there's no agreement upon which resistance indicates which current. Others use a true computerized negotiation, but again there is no common protocol - and some manufacturers use that negotiation as a means to lock-out third party chargers by deliberately not disclosing the protocol, or even using cryptographic authentication.
6. Re:*yawn* these have around for years? by Psyborgue · 2013-09-15 20:38 · Score: 4, Informative
  
  Also there are many phones that will refuse to charge *at all* without these pins.
7. Re:*yawn* these have around for years? by ThePhilips · 2013-09-15 21:18 · Score: 4, Informative
  
  That said for the portable device on the other end to recognise charging mode it also needs to see some fixed resistance, which would need to be build into the far end plug too.
  Samsung's charger for the Galaxies simply shorts the data pins. (No, not the cable. The charger.) They do it as a way to recognize that it is a charger connected and allow drawing more power.
  
  --
  All hope abandon ye who enter here.
8. Re:*yawn* these have around for years? by FatLittleMonkey · 2013-09-15 21:26 · Score: 4, Informative
  
  [sigh] So much for "Universal".
  
  --
  Science is all about firing a drunk pig out of a cannon just to see what happens.
9. Re:*yawn* these have around for years? by fuzzyfuzzyfungus · 2013-09-15 22:39 · Score: 4, Informative
  
  Based on some unpleasant experiences with a USB printer that had a neat internal short, my impression is that a device has to be really nasty to just die when subjected to excessive attempted current draw by a peripheral. You actually do get a little 'host reset' message and no permanent damage, really rather civilized. I don't know whether it's something clever or just a re-settable fuse; but it doesn't seem to result in the hard-kill you'd expect from an ordinary fuse.
  
  For compatibility purposes, though, all kinds of attempted power draws that are off-spec but below whatever the device considers dangerous are generally well tolerated. USB HDDs drawing ~800ma, or connected to the data lines of one port and the power lines of a second port, little fans and LEDs on goosenecks, all kinds of nasty stuff. Especially on desktops, where +5v is available in nigh-unlimited quantities. Laptops and routers and things, with actual power budgets, seem to be a bit pickier.
10. Re:*yawn* these have around for years? by fuzzyfuzzyfungus · 2013-09-15 22:41 · Score: 5, Funny
  
  [sigh] So much for "Universal".
  Hey, man, not my problem if two passengers don't get along, I just drive the bus.
  
  -USB Implementors' Forum, Inc.
11. Re:*yawn* these have around for years? by Anonymous Coward · 2013-09-15 22:52 · Score: 5, Informative
  
  The host power lines are usually protected by a "polyfuse" (aka self-resetting fuse), sometimes just one for all lines combined if the total current is no danger to the traces should it be drawn from one port. A polyfuse is a (normally small) resistance which is designed to go into thermal runaway when the current limit is exceeded. After a few minutes without current, the fuse "resets", i.e. it cools down sufficiently for the resistance to drop far enough that the normal current won't trigger the thermal runaway.
12. Re:*yawn* these have around for years? by AmiMoJo · 2013-09-15 23:30 · Score: 5, Informative
  
  Actually there is a standard, laid out in the USB Battery Charging Specification. It clearly states that a dumb charger should short D+ and D- directly to indicate that it can supply up to 1.5A.
  The only company that uses resistors is Apple. The USB spec was released in 2007 so maybe their early devices pre-dated that. In any case, any properly designed USB device from the past 5 years should fast charge from a dumb charger simply by having the D+ and D- lines shorted.
  
  --
  const int one = 65536; (Silvermoon, Texture.cs)
  SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
13. Re:*yawn* these have around for years? by JesseMcDonald · 2013-09-16 05:44 · Score: 5, Informative
  
  Is there some term that is used to distinguish connectors with / without this functionality, so I can buy the right kind?
  I gave up on finding USB Charging Specification-compatible chargers a while ago and just picked up a "charge-only" USB cable, which does the same thing as the adapter in this article: short the D+ and D- pins on the device side. This lets any standards-compliant (i.e. non-Apple) device know that it's safe to charge at full speed, so it should fix the problem so long as your charger can handle the current.
  You can tell whether an Android device is charging properly by looking at the Battery pages in Settings. It should say "Charging (AC)" to indicate a full-speed charge, or "Charging (USB)" to indicate that it's limiting itself to 100mA.
  
  --
  "The state is that great fiction by which everyone tries to live at the expense of everyone else." - Bastiat
Re:Not Completely Safe by smash · 2013-09-15 18:14 · Score: 5, Insightful

If someone has physical access to your phone unsupervised, ALL BETS ARE OFF.

--
I run: Windows, OS X, Linux, FreeBSD. Just because you have a hammer, doesn't mean everything is a nail.
You can do this with a USB extension cable... by chaboud · 2013-09-15 18:14 · Score: 4, Informative

I've made my own, but you can buy them inexpensively. They're really convenient if you're, say, trying to keep devices from popping the VMWare Fusion Mac/Linux selection dialog or complaining about ejection.
So, yeah, this guy made a board, but a cut-line extension cable has been the answer to this problem for a while. Some devices may fuss or trickle charge, but it generally works.
What does the electronics do? by irp · 2013-09-15 18:22 · Score: 4, Interesting

I've apparently made 'USB condoms' myself. A male and female usb connector soldered end-to-end, the data pins shorted together.
This enables my ancient HTC Desire to recognize any usb charger as a dedicated charger, and charge with up to 1 A (in reality significantly less). It is a low tech solution that works.
So why so much electronics on the board??
Re:Fast charge detection by tjohns · 2013-09-15 18:31 · Score: 4, Insightful

These boards have quite a bit of logic on them. If they were just cutting the data pins, that would all be unnecessary.
The product page is light on details, but I'd be surprised if that logic wasn't there precisely to negotiate charge rate.
Re:Fast charge detection by jamesh · 2013-09-15 18:34 · Score: 4, Interesting

They can still try to draw 500mA and let the host cry. I don't know if they will, but wall chargers don't seem to have a complex protocol setup, I don't know how the do it.
I had an aftermarket iPhone charger for my car that was a cigarette lighter adapter with a USB socket on it and then a USB to iPhone cable. One day I was in the office and needed to charge my iPhone and didn't have a charger so I grabbed the USB cable from my car. The moment I plugged it into my laptop, even before plugging the iPhone in, the laptop turned off. No damage. Being naturally curious I tried it again and it was repeatable.
I'd go as far to say that some are basically brain dead
Re:So, if I manufacture chargers.... by jamesh · 2013-09-15 18:37 · Score: 5, Funny

You could do that. I could also not buy your broken charger.
But you know what you're doing. Social engineering will always work on some people though:
"My phone is flat and I really need to take a photo of my big mac to show my friends, can I borrow your charger?"
"Sure, here you go"
"It's not working"
"Try taking that adapter thing off, it's probably mucking up the charging"
Faced with the horror of eating their big mac without it first being photographed, I think you can guess how this story ends...
Not the only one out there by ericfitz · 2013-09-15 18:37 · Score: 5, Interesting

There's a current KickStarter project called LockedUSB which does something similar, but which also includes a power management chip in order to negotiate higher power charging levels that normally require data connectivity. LockedUSB doesn't appear as big or ugly as the one in TFA. (Full disclosure: I'm a backer)
Re:Condom. You keep using that word... by jamesh · 2013-09-15 18:38 · Score: 5, Insightful

A little company called int3.cc has developed a product—a USB condom—that blocks the data pins in your USB device while leaving the power pins free.
If you consider something that blocks the middle of the male end but leaves the sides open to be a "condom," you might want to see a doctor. Soon.
If you consider that it allows for insertion without allowing the flow of information, the comparison might be more correct than you think.
Re:Half-plugging has the same effect by aXis100 · 2013-09-15 18:46 · Score: 4, Funny

Just the tip you say???
Re:Condom. You keep using that word... by drkim · 2013-09-15 18:59 · Score: 4, Funny

A little company called int3.cc has developed a product—a USB condom—that blocks the data pins in your USB device while leaving the power pins free.
If you consider something that blocks the middle of the male end but leaves the sides open to be a "condom," you might want to see a doctor. Soon.
If you consider that it allows for insertion without allowing the flow of information, the comparison might be more correct than you think.
Yes. But I hate charging with these 'cause it just doesn't feel as good...
Re:So, if I manufacture chargers.... by smash · 2013-09-15 21:03 · Score: 4, Insightful

Well... if you're going to remove a device specifically designed for device security because some unknown third party device/person tells you to - your security problems aren't of a technical nature. As they say, there's no technical fix for stupid. Not saying it won't happen, but there's not a lot a security accessory vendor can do to protect against that.

--
I run: Windows, OS X, Linux, FreeBSD. Just because you have a hammer, doesn't mean everything is a nail.
Re:Not Completely Safe by robthebloke · 2013-09-15 21:06 · Score: 5, Funny

That's why I tamper-proof my phone with Windows 8, and a picture of Justin Bieber for the locked screen.
Re:So, if I manufacture chargers.... by MrKaos · 2013-09-15 21:50 · Score: 4, Funny

All I have to do is feed some "connection error" kinda stuff on the screen until the guy takes off his condom.
For anyone new here this is a fine example of geek sexting...

--
My ism, it's full of beliefs.