I'm amazed at how many apologists there are for these pitifully-designed connectors ... and I include the HDMI connector in my disdain for the whole class of micro-miniature connectors. I've only experienced one outright failure, but I'm constant annoyed at how difficult it is to align and mate them. All these folks should take a lesson from RJ-45 and similar connectors ... in their smoke-filled backrooms when they conjure up these standards!!
I can't speak to the reliability of the host port connectors (Type A), but I agree that the design ergonomics are poor. My success rate is well under 50% - I rotate the connector 180 degrees multiple times until it feels right, not wanting to force it. While more obvious polarizing would be helpful, why have the polarizing at all? Just make the dang thing work either way you plug it in.
On the device port end (Type B), though, we have experienced poor reliability. The PCB connections break, the connector internals break, but the weakest part of the design appears to be the little plastic center post. Quality varies slightly between manufacturers, but none are very tolerant of a side force. If you are skeptical, try it yourself. Just plug the USB-B connector into a device port and give the cord a sideways jerk. You'll be surprised at how easily the center post breaks, making the connector useless. Imagine picking up a device, such as a USB printer, to move it, but forgetting to unplug the USB. There's your sideways force right there.
We are designing out the USB-B connector in favor of the Mini-B. Our testing and experience have shown it to be a much more reliable connector for us.
Many, but not all, USB cables or devices have the USB simbol on the top of the connector, so those ones you can count on getting right 100% of the time. A bigger problem for me is that the USB connectors on many PCs are too close together for the plasic plug ends on the cables or thumb drives to be pluged in side by side. That is irritating and inexcusable. I also have a Flip video camera that you cannot plug into the PC with the screen side up, so I can't tell if it is operating or charging. It also exceeds the current available from the USB port on many devices including dedicated USB chargers.
Perhaps the earlier USB connectors were more mechanically rugged, but as they moved toward the commodity status they got cheaper and cheaper, which usually happens as quality is removed.
The reductions in quality don't usually show, such as a cheaper grade of plastic, thinner and softer metal, less elaborate methods of keeping the contacts in place on top of their plastic base, and the whole metal shield not extending into the plastic over-mold portion as far. Exactly the same quality reductions can be found on some HDMI connectors, most of which function as well as the more costly ones. The difference becomes clear when they suffer any abuse at all, and consequently fail. That is when we find that running the outer shell only 0.085" into the plastic overmold does not anchor it vary well. If that same outer shell extended back 0.25" into the overmold the connector would be quite rugged, and it would survive a lot better. That is where the cost reduction engineering shows up, which is when it is exposed as quality reduction engineering.
REally, for ruggedness in dry environments it is hard to beat the 9, 15, and 25 position "D" connectors.
I've seen mashed and broken pins on mini-DIN connectors (PS/2 keyboards and mice) and subminiature D connectors (parallel printers, serial ports and VGA video ports), but I have yet to damage an USB connector. They're rugged and well designed for devices in their price range. Moreover, the network symbol is embossed on one side of the "A" and "B" plugs to make it possible to blind-mate them. That's by design and specified in the USB standard.
If you have a problem with wearing USB receptacles out or breaking them, consider using wireless links instead. One can get printers, keyboards and pointing devices that use Bluetooth, IRDA or Wi-Fi, which can reduce the frequency of mating and unmating cables from the computer's built-in USB port. Also, instead of wearing out the computer's USB port, plug a cheap USB 2.0 hub into the port and wear it out instead. A hub can be obtained for less than $10 these days.
Good final question, Car Analogy. The comments to the posting may indicate that the USB-A did get it right. When I plug a USB-A into my laptop and I have it the wrong way (because mine is on the side), I'm not likely to break anything. It doesn't take much pressure to find out I don't have it in right.
I use white typewriter correction fluid ("White Out" with various permutations of spelling) to coat the USB symbol. Some connectors are inverted, but the trick works in most pairings and saves much frustration.
At this year's MD&M West show, lots of material suppliers are talking about new formulations for wearables and things that stick to the skin, whether it's adhesives, wound dressings, skin patches and other drug delivery devices, or medical electronics.
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