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Some Reversible USB-C Cables/Adapters Could Cause Irreversible Damage
TheRealHocusLocus writes: Three Decembers ago I lauded the impending death of the trapezoid. Celebration of the rectangle might be premature however, because in the rush-to-market an appalling number of chargers, cables and legacy adapters have been discovered to be non-compliant. There have been performance issues with bad USB implementation all along, but now — with improved conductors USB-C offers to negotiate up to 3A in addition the 900ma base, so use of a non-compliant adapter may result in damage. Google engineer and hero Benson Leung has been waging a one-man compliance campaign of Amazon reviews to warn of dodgy devices and praise the good. Reddit user bmcclure937 offers a spreadsheet summary of the reviews. It's a jungle out there, don't get fried.
If you're relying on the cable having enough intelligence to prevent the two devices from hurting each other, you've already messed things up.
This is a new development. Benson Leung found a cable so bad it destroyed his analyzing equipment, and he says he won't be able to do reviews anymore because of it. The cable was actually missing wires internally, among other things.
"First they came for the slanderers and i said nothing."
When it comes to USB, test your equipment, even if you haven't upgraded to Type C yet.
I've personally discovered two counterfeit or substandard (depending upon your personal definitions of the terms) USB charging cables.
What I use to test is a Samsung Galaxy Tab 3 10-inch tablet. This tablet wants approximately 0.7-0.8 amps at 5 volts, but it will charge in a degraded mode if the charging cable isn't up to snuff, or if it's plugged into a desktop or laptop (which normally only supply 0.5 amps).
Every cable should begin by charging in the degraded mode when plugged into my laptop and then upgrade to normal charging mode when plugged into any of my half dozen or so 2 amp USB chargers. Among over a dozen cables, I detected two that were not up to snuff, and you'd be surprised at my results. One cable from the dollar store was garbage, but another, colored cable from the dollar store that had fancy LEDs was fine. Three 10 feet cables were fine. The other reject was an average-looking cable with an average feel. It did not appear to be substandard or counterfeit.
If you want to get fancy you can get a device from banggood.com that measures current and voltage across the USB port. They cost about $3 shipped. That is how I determined that my tablet will draw approximately 0.7-0.8 amps. From that experience I'd be surprised if many devices actually draw a full 2 amps. It's nice to have a 2 amp supply, though, because it gives you a safety factor if your cables are somewhat substandard. Maybe the newest 2016 phones will draw close to 2 amps. Get the meter and find out!
Based upon my experience, the best USB chargers are from Samsung and anything else that has a counterfeit-resistant UL sticker. And also based upon my experience, if you notice that a charging cable is getting warm, you should probably replace it because it's dissipating electricity as heat rather than conducting it.
The missing wires weren't the really bad part - the result of that would've "merely" been that it wouldn't work as a USB3 SuperSpeed cable and only connect in USB2 High Speed mode.
What really set that one apart was that it had VCC and GND swapped on one end.
We need inexpensive reliable testers for usb cables. Basically a box where you plug the cables in and it does the various electrical tests.
Isn't the whole point of standard that the consumer should know that two devices are equitable in abilities?
The problem here is the owner of the USB 3.0 spec is not releasing their legal hounds on companies manufacturing "USB 3.0" cables that don't truly support the standard.
You should never be able to permanently damage a grounded device by connecting something to its ground line. The ground line should be safe for all sane voltages (all bets are obviously off with lightning). On laptops and phones and shit this is a problem because they aren't grounded and have to dump out to the case or something. Even when plugged in, many laptops aren't grounded.
Modern motherboards advertise physical USB port protection for such bullshit precisely because it's becoming a more common issue with shitty USB devices and cables. It's not a USB 3 problem it's a USB and shitty implementations problem, but that's what happens when you commoditize so hard that all anyone ever does is buy the cheapest item listed that ships with Prime.
ahem... http://www.ibtimes.com/apple-r... http://bgr.com/2014/06/13/ipho... http://bgr.com/2015/06/03/appl...
It's a shame that USB went with Vbus/Gnd rather than V+/V-. The latter would allow the negative side to drift away from ground (which is typically kept on the shield in a zero-current path). They had to devote a small section to voltage drops it in the latest spec (3.6.10.1 in USB_PS_R2_0 V1.1: bottom line is 375mV of Gnd rise and 625mV of Vbus drop).
The Ethernet guys realized this would be a problem so they made their signals transformer isolated. But USB is designed for short runs and cheap interfaces, not 100m runs across different electrical grids.
Note, however, that this case was not related to the ground potential at all. Vbus and Gnd were reversed, exceeding the Vgnd_drop limit by over 9V (2400%), or possibly 40V (>10000%) if the device had managed to negotiate the new voltage limits before it died.
One connects to all of your devices and accesses the data, the other is a hardware standard.
There is an organization that certifies USB stuff. If a cable has a little sticker with that certification logo, it's probably good.
Not sure how much they do to prevent unauthorized use though.
... also, I can kill you with my brain.