USB inventor explains why the connector was not designed to be reversible
Someday we'll look back and laugh (or cry) at our early USB struggles.
TL;DR: its cheaper that way,
And i value that decision
I can bet you it's incompetence. They failed upwards. Sure, protocol is great and universal, but connector is atrocious and it has nothing to do with cost. Few points in favor of this hypothesis:
Initially, the plastic inside the connector was white. They started to use black to denote USB2.0 devices, and USB2.0 rapidly became the standard. They at least tried to do something similar with blue plastic with USB3.0.
It's basically the only example I can think of where the plug and socket are rotationally symmetrical without also being reversible. That's the kind of thing where I ask "did you test this before you shipped it?" Thirty years later we're still plagued by the damn thing.
Also a male USB 2 plug fits perfectly into a RJ45 slot :-/ In my days of tech support, I've seen multiple people plugging their USB printer cable into the network slot of their computer and it's a perfect fit so they were always convinced they didn't do anything wrong... That's clearly a design flaw while all other connectors have distinct sizes.
No one ever had doubts how type B or mini B or micro B go in.
I agree with most of your post, but micro B is a step too far. That fucking plug was always inserted with the following procedure:
Always, always, always.
Considering the much higher cost of production then vs now, it makes complete sense. The economy of scale took care of that problem with time.
USB-A walked so USB-C could fly.
EXPLAIN!
It doesn't necessarily need to be 4-dimensional https://en.m.wikipedia.org/wiki/Spinor
USB-A is a spin-half connector type
Purged by creator
Somewhat understandable, but they could've also done something like HDMI and DisplayPort and gone with a shape that could only plug in one way. It might not have been "as cheap as possible" but probably not as much added expense as the extra wiring and stuff. (maybe, idk shit about manufacturing)
I really wish hdmi was symmetrical. (Peer behind tv, “which way goes up?” Tries to plug it in, “fml it was the other way” flips it drops it)
Not all asymmetric port designs are good. SCART was capable – HDMI of the 1990s-2000s – but you cannot really feel where one ends and another begins with 2-3 of them in the rear of almost every TV and VCR sold in Europe back then. They carried flawless RGB video, two-way composite A/V, remote control signals etc. However, they were bulky (why 21 individually shielded wires instead of twisted pairs?), expensive and got loose easily. This was before digital technology that enabled error correction and multiplexing.
About a decade ago or so, I found myself in a reddit argument with someone that claimed they had never attempted to plug a USB in unsuccessfully. They said that every single time they've plugged in, it was the correct way. Some people are insane.
Honestly, with high quality USB A plugs you could feel the logo on the side that was "up", and if you knew which side your motherboard or front panel considered "up", it'd be easy to always plug devices in correctly.
Just that the vast majority of manufacturers stopped caring relatively early on, which meant you couldn't rely on it anymore.
They're supposed to label the USBs so that you can tell which side is the top side and which side is the bottom side.
The problem is that, A they often don't label them and, B I can't remember which way round it's supposed to go anyway, so it wouldn't help.
Most things I have are labelled properly, and I'm only hedging my bets by saying most because I can't think of anything I own that isn't labelled properly
That wasn't so hard, was it?
I feel like that's a way to rapidly run out of spare universes
Perhaps a controversial opinion here, but the usefulness of reversibility is vastly overrated. It's not a game changer, just a tiny first-world luxury that's nice to have, but it does it by introducing a bunch of unnecessary complexity that I'd rather avoid. Not worth the trade off IMO. I can count on one hand the number of minutes USB-C has saved me by being reversible and I honestly don't care
The issue is that USBC was the first standard to really take the mechanical design process seriously in a consumer context. In doing so, it was made both way more ergonomic and way more durable. I'd argue that without the focus on some of these "small but marketable" consumer-oriented bits, we would not have gotten the great overall connector design we did.
Engineering centric worldview versus user centric worldview.
I am just laughing here because I spent the day dealing with ancient serial tech pigtails and DB9s. You people have no idea the pain of losing multiple days of your life trying to get RS-232 to work. Especially when stuff doesn't follow the standards it is supposed to follow.
Yes, you're right: that was controversial.
Did you burn the witch?
Yeah, that's an easier test, you don't need huge scales and a duck
Maybe he did it only once and worked out of luck.
I mean if you tend to plug things in at the same computer a lot it's pretty easy to always plug things in right the first time, even when not looking because you just kinda know what way it's meant to be. And laptops usually have all theirs pointing the same way so you know one you know them all. If something has text on it, it's usually oriented in such a way that when plugged in you can read it. Or they have a little face and you know which way the face is meant to be facing
I have a similar "power" and while I'm not flawless, it's only really new or unfamiliar devices/computers that trip me up. Or plugs that don't actually have any identifying features and/or unusual ones
Well, I rarely fail because I look inside the connector and see where the plastic is and then plug it properly. I tend to fail when I cannot see inside the connector because it's in a weird spot.
I guess the redditor was either bragging about always looking inside or was a kid
I wouldn't say it's never happened to me but 99% of the time it works. I just look at the idents, face it right way up, and shove it in. Unless I'm drunk or it's dark, I've never been able to relate.
Overall not a huge deal to get it wrong occasionally, but to lie that you've never attempted to plug a USB in the wrong way up is insane.
If you can see through the two rectangular cutouts on the plug, it's the right way around. Unfortunately, this doesn't help if the plug is turned 90°, and also some computers have it upside down (looking at you, GPD).
I wonder how that redditor is doing now? Still batting 1.000 with USB A adapters?
If it's on a laptop I could see it. The empty half almost always needs to be on top on the male side because the female end is almost always plastic on top.
But in practical use, people found out that even a 50/50 chance of plugging the connector in the right way is annoying enough to warrant the additional complexity of reversability, hence the development of USB Type C.
The USB-C design turned out to be much more durable and versatile (signal and power wise) in addition to reversability compared to the previous USB designs, and it is developed specifically to address the problems people found with USB-A/B/MicroUSB.
Sometimes problems only reveal themselves through real life usage, and iterative improvement through a scientific trial and error process to address these problem is how you get development progress.
For USB-A, it's usually not even 50/50. It's the witchcraft superposition when the first two tries don't work.
It always works the third time, 60 percent of the time.
Yeah, people don't take into account quantum positioning, pass-through phenomenon, or the fact that I can't "see" when I plug it in wrong and that makes me think maybe my fingers are dumb and I missed the hole and not that I need to reverse it and try again.
First try doesn't go in: oh I guess I have to flip it. Second try doesn't go in, fiddle it a bunch still doesn't go in. Fuck I had it the first time. Third try goes in immediately
USB-C has more connectors for data and power than A/B so it's not a surprise that it's more capable.
What's really changed is demand. No one really expected USB to be used to power everything, it was only ever really expected to be used on computers and maybe digital cameras, smartphones used to arrange matters for themselves. It was only when they two began to adopt USB aas well that calls for smaller ports and higher capacity cables started to arise.
Can someone explain to me why I keep reading about people having problems plugging in USB A connectors upside down? I feel like I'm taking crazy pills. Per the spec, the holes always go up. They indicate the correct way to plug in the port. Not only that, but the printed logo on the connector also always goes up.
The only time this is SLIGHTLY confusing is if you have a desktop tower where the motherboard is essentially mounted sideways, but for that case it just takes an extra second to think which way is "up" from the perspective of the motherboard.
And before anyone says "who reads the spec?", it feels like I subconsciously knew this for something like a decade before I even knew what a spec was.
Sometimes you're working on an IoT device in a tight space, which makes rotating/seeing everything much harder.
Especially if you drop the cable it falls into a crevice somewhere.
You probably won't have trouble plugging it in the first time, but gods forbid you unplug/replug it then the cable rotates 540 degrees and you have no idea how it was plugged in before
It’s not an issue of not being reversible. The problem is that it is symmetrical without being reversible. HDMI and DisplayPort are much less annoying. Even USB Type B (printer cables) is relatively easy to figure out orientation for.
I actually think that a big part of the problem isn't reversibility or symmetricality, it's that that the ports themselves are not designed in a way that easily accepts the cable blind, and I think the best example of the way it should be is probably the SCOMP link. Or for those of that aren't super nerds, the star wars connector that R2 uses to stop the trash compactor, amongst other things.
Look at that thing. R2 could be stumbling around drunk after a weekend droid bender and still find the target. Now, I'm not saying that it should be that large, but imagine fi the receiving port had a 1-2mm meniscus like curve that allowed you to find the target more easily, especially combined with a modern cable like USB-C. If we just look at the physical shape of the connectors, I think Lightning actually got this more correct than just about anyone else - look at a Lightning connector, and the male end has a very small curve on the sides of the connector to make it easier to actually get into the port. The female end also has a very subtle version of the thing I'm talking about.
I think a real life connector should have a slightly more prominent version of this, especially if it's going to be the one connector for literally everything. Like, plugging into the back of a monitor or PC you can't quite reach or TV or something should be an easy no-look operation. I've ton tech support for decades, and there is basically no connector that doesn't absolutely suck shit to try to plug in if you can't actually see it. I want to be able to throw it from across the room and still have it stick though.
For more on this topic, buy a coffee in a DT in a place that has to hold the reader out for you. Your dumb meat body is holding the card and moving slightly, the dumb meat body of the person taking the payment is moving slightly, so you end up try to jam the chip in a way that makes you both feel like you have a stack of learning disabilities. It's just bad design.
they should just go with perfectly circular, with different sizes for different applications. imagine a 20mm unit - high power/bandwidth hoses with a satisfying locking mechanism that magnetically seals the connection.
and makes the proton pack sound. and rgb fuck nevermind go back this was a bad idea
Circular isn't a great idea, and here are most of the idea why it is not : https://electronics.stackexchange.com/questions/528821/why-dont-we-have-a-circular-usb-port
USB required to have a stable connexion, as it's a digital signal and not an analog as jack ports, which just sends curent through it. Rotating the connector could maybe introduce issues for signal integrity.
The usb connector has much more connectors than a jack port. It would take a very long hole to fit them all. (usb 3+, usb C...)
Size constraint. USB C is flat, a round port is not. So it's bigger in 1 way, but smaller in the other, and so creates more design challenges.
Round is not round, that is, there's a difference between the likes of cinch and DIN (-style) connectors. Cinch can be rotated once inserted which indeed isn't ideal, but DIN are perfectly adequate signal-wise and you can rotate them into place, just like finding the begging of a thread when inserting a screw.
Keyboards used five-pole DIN for the longest time and mice D-Sub (because serial), both changed to Mini-DIN 6, aka "PS/2 connectors". And never, ever, did anyone complain about getting the orientation wrong with DIN connectors.
D-Sub are a bit iffy but at least you really do have a 50/50 chance as they don't jam like USB-A does. They also aren't actually rectangular and you can feel the matching angles on both female and male ends.
Really, connectors went downhill with USB. HDMI and DisplayPort aren't really any better as you can't feel the shape of the socket, either. OTOH, one really nasty connector becomes rarer and rarer: Molex. Also you can't fry your motherboard by connecting the main power connection in the wrong way, any more (remember: Black to black).
Charge your electric vehicle with USB-H ("H" for Huge)
this, but the plug in and unplug sounds should be 40db louder.
Wouldn't fit very well into something like a smartphone though
You say bad idea, I say sign me up!
I get why it's not reversible. But why the hell is it not keyed so that is obvious which orientation is correct? A small, cheap, notch would have worked wonders.
Almost all connectors in use on computers at the time USB was introduced were already keyed, and a fat lot of good it did us. Ask anyone who tried fumbling around behind a three ton CRT monitor or computer case -- even with the keyed connectors, feeling for which side was up, getting anything plugged in without eyes on it was already nigh on impossible.
What the USB A connector did do which was new at the time was introduce a connector that did not have any protruding pins on either the male or female end, and thus theoretically at least could not be damaged by fucking up the insertion. Unlike any of the then-common D-Sub connectors (VGA, serial, parallel) or DIN (PS/2 mouse and keyboard, Apple serial, S-Video, etc.). USB didn't even have the little clip to breal off like an RJ-45 Ethernet or RJ-11 phone line connector.
What the USB A connector did do which was new at the time
Gameboy Link cable did that earlier and subsequently inspired the Firewire connector (and also happens to look a little like Type-C with the contacts in the middle).
What the USB A connector did do which was new at the time was introduce a connector that did not have any protruding pins on either the male or female end, and thus theoretically at least could not be damaged by fucking up the insertion.
This is not true.
Some 80s computers had cassette player interfaces that practically looked like big USB connectors.
https://www.rarecomputers.com/wp-content/uploads/2019/11/back-picture-c64.jpg
There were the early USB plugs that were sort of weird notched trapezoids about 8 mm square (predecessor of mini and micro, USB-B). I always thought those were fine.
Actually looking at this I'm surprised how many other styles there were.
The problem for me was never the plug, but the socket. It was obvious to me which side had the connectors, it's the sockets on devices that would be random rotations most of the time. I never really understood the extreme hatred, while it wasn't perfect, it worked well. I inserted successfully a lot more times than not, USB-A served us well in all honesty, but glad we have moved on to reversible.
Keying does no good, have you tried fumbling with a serial port connection before? Same difference, and it's keyed too.
What'd have helped is clear markings and plug heads, like how some DIN connectors are done: The orientation simply cannot be missed.
Yeah, it's orientation I mean more than keying. USB-B was much easier to plug in than A. Orientation is very clear.
Some USB sticks have the logo on one side, some have it on the other...
the decision was made to go with a design that, in theory, would give users a 50/50 chance of plugging it in correctly
How could it be less than that? If it was triangular?
The PS2 (and AT) connectors keyboards and mice were largely using before USB were round…
Arguably still better though because you could just rotate the plug until it went in instead of flipping it back and forth 5 times to get it to go in. And they also had more reliable indication for orientation.
You know all the jokes about getting usb's orientation right on first try, failing to push it in and trying the other way? Yeah, it was already worse than 50/50.
Honestly that connector always felt like shit. A tiny, easily identifiable mark/notch/whatever on both plug and port would have made it a lot better, even if it was still non-reversible.
Oh god please don't give them ideas...
How many other plugs are reversible? HDMI and DisplayPort aren't. Older stuff like scsi, gameports, parallel and serial ports and the like weren't, and could even destroy your hardware if plugged into the wrong thing. Firewire and GameboyLink weren't. Barrel plugs are insertable every way you want, but only have two contacts. And 3.5mm jacks slide over all the pins, which might not be great if you plan on carrying power.
Lightning and USB Type-C are reversible, but that's the only one I can think of. And the inoffiziell rarely seen reversible USB Type-A (when were those first released?).
Biggest problem with USB Type-A is that it isn't keyed in an obvious way, so both directions of insertions look and feel plausible until the thing doesn't wanna fit.
PS: Another thing "wrong" with USB is that Type-B isn't a female Type-A, but a completely different thing, meaning a USB cable can't be used as extension cord and you need a different cord for that. As I understand it, this was done deliberately to avoid issues with cable length and voltagedrop and signal degradation (which you run into anyway when using USB extension cords). There is also the hermaphroditic connector, which keeps the sides the same, while still allows extension cord use. Don't know if anybody ever implemented that.
Most people weren't adding and removing peripherals (and potentially multiple things using the same kind of connector) from their computers multiple times a day when many of your examples were in common consumer usage.
Now we plug and unplug peripherals all the time, and for a great many people those multiple plug/unplug cycles are all using USB, and have been long enough to have plenty of frustration about this.
I don't think Type-A or its creator should burn in the depths of hell, but it's a legitimate complaint for a usage case that most people didn't experience prior to loosely about the time that USB started to rise in popularity, or so my recollection of the chain of events tells me.
Depends, back in the home computer days swapping around joysticks and mouse (and less often lightpens and paddles) was a pretty common occurrence. And over in the console world we had multiple gamepads, multitabs, GameBoy Link cables and the like that also saw a ton of plug-in action.
PC was somewhat special, since joysticks, keyboard, mouse and printers all used different ports, often only accessible on the hard to reach backside of the PC case and sometimes even screwed in. Hotplugging was also not officially supported. Those are however all the issues that USB was specifically designed to fix, so more plug-in action was to be expected.
That said, it is quite true that reversibility really wasn't a concern back than at all. None of the other ports had it, and USB was a huge improvement over previous PC port designs.
I think the big thing with Firewire and DisplayPort, though, is that the port isn't a rectangle. It's flush on one size and angled on the other so that you know which way it plugs in no matter what. It being non-reversible wasn't an issue because of that. USB, on the other hand, has the same shape whether it's right-side-up or upside-down.
IBM token link connectors were hermaphroditic
Didn't have to be reversible. Just obvious. Both HDMI and DisplayPort go in only one way. It takes fiddling but there's no doubt. With USB it's always you fiddle, doesn't fit, then maybe it's the other way around, doesn't fit, oooh it was the original, doesn't fit... ffs. And they even made the plastic black.
I must be dumb cause I still need 3 tries to plug in a HDMI/DP port.
USB B takes 6 tries: first three times in a RJ45 port, then 3 more after realizing I've been messing with the wrong port all this time.
I used to work in a call centre and a lot of headsets use that connected design.
Neat, never heard of that, guess it's not seeing much use outside the professional setting. It's called Plantronics QD.
TL:DR; It was cheaper and they figured if it didn't work you could flip it over and try again. So it's mildly inconvenient to save a few cents on manufacturing each connector and to limited the number is conductors to 4, something it turns out was a bad idea anyway because newer USB standards use more than 4 conductors.
I don't get the "more than 4 conductors" bit, wouldn't you just have to change the plug with contacts on the top and bottom? I assume that's how the reversible Type-A cables work.
That is one way to deal with the problem, but it comes with its own tradeoffs. In particular that reversible type-a is incredibly fragile due to how thin the plastic supporting the pins needs to be to fit within the housing. They could make the plug bigger of course, but now you're adding more cost and decreasing the areas the plug can potentially be used in due to its increased size. Conductor routing also becomes more problematic as you need to cross conductors to opposite sides now. Additionally while that cuts down on conductors needed in the actual cable, you still end up needing 8 pins/conductors in the plug, one set of 4 on each side of the plug.
Making USB reversible to begin with would have necessitated twice as many wires and twice as many circuits, and would have doubled the cost. Bhatt says his team was aware at the time of the frustration that a rectangular design could have, versus a round connector. But in an effort to keep it as cheap as possible, the decision was made to go with a design that, in theory, would give users a 50/50 chance of plugging it in correctly (you can up the odds by looking at the inside first, or identifying the logo).
I was there when we had lots of "round" connectors like Din connectors but also lots of proprietary ones.
That was way worse, trying for the eleventh time to put it in correctly without looking as it's under/on the backside in a jungle of other cables, and not damaging any of the fragile 7 pins... gargl.
The trick with DIN connectors was to try to insert them gently while rotating them. Once you got the notch lined up they would very clearly drop into the socket at which point you could apply more pressure to fully seat them. It was only a problem if you were jamming them in full force while rotating because you could exert enough pressure to force it into the socket even with the key notch misaligned crushing the pins. I never once had a problem inserting a DIN connector, something I absolutely can't say about USB-A.
Wow I'd forgotten about the old keyboard and mouse ports, they were such a faff to plug in without looking.
would give users a 50/50 chance of plugging it in correctly
Sometimes it's more 33% or even 10%.
I have my doubts. I think that a jack-like (circular) connector wouldn't require twice as many wires and circuits. Actually absolutely the same amount. The connector itself would require more metal to make.
And the chance of correctly plugging that in would be like 99/100 (1/100 for breaking it).
What a pathetic excuse. You know what's at the other end of a USB-A cable? A USB-B connector that didn't have the symmetry problem. Also, Firewire existed around the same time (in fact, slightly earlier) and didn't have the symmetry problem.
the problem is the plug is rectangular (has exterior rotational symmetry) AND not reversible - if the plugs were L shaped it would be clear by both feel and brief glance which rotation was correct
The worst thing about USB is that it always takes 3 attempts on average to get the fucker in if you don't know the orientation of the port.
Which proves that is has 4 dimensions of space!
That would explain why they were able to fit so many gigs into such a small little device and sell it for like, 20$.
To save a penny on each connector. The USB group is ran by hardware manufacturers. They do not have innovation as a core value.
I learned a long time ago that it takes three licks to get to the Tootsie Roll center of a Tootsie Pop, because commercial breaks during Saturday morning cartoons told me so. Sometime later, I also learned that "three" is usually the magic number for correctly plugging in a USB Type-A device.
……what the fuck?
Edit: Guys, I get the reference to Tootsie Pop ads and that USB-A connectors are often stubborn to connect. The “wtf-ness” comes from the writer making such an oddball reference just to arrive at the number three
If you're still confused, it's an apparently universal experience to try to plug in a USB, feel resistance, flip it, feel much more resistance, and then realize you were correct the first time. Hence, three is the magic number.
Yeah no I get the reference
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Reminds me of how we used to change the order of the wires in PC to PC connections on early RJ45 cables. What a fucking pain in the ass that was for colorblind like myself.
I had always wondered what that was like for colour blind people.
Let's just say that I didn't do too well when I wanted to become a helicopter engineer. Color coding is one of those things that are both inevitable and impossible.
Ah yes: "crossover or straight through?"
I actually have some USB-A to USB-C cables from DeWalt with reversible USB-A connectors. Certainly no reason other companies couldn't have built them that way.
Yeah, I bought some JBL sound equipment and those USB-A side cables are reversable too. Just a flap with the connectors on both sides.
That's such a simple reason and makes so much sense.
Money? It’s pretty much always the reason.
People who find that "frustrating" have led too sheltered a life.
While I agree this is no big deal, but I also don't think anyone is saying this is the worst problem ever. Another person starving doesn't make me any less hungry. I don't think it's super helpful to say what is and isn't annoyance/problem for people.
It's not a big deal but add up the billions of times people needed to plug a USB 3 times instead of one and that's a lot of wasted hours.
*with the exception of some who have specific disabilities
It can be frustrating without being the most frustrating thing. Mild annoyance repeated many times becomes pretty annoying.
But why is USB C directional? One phone I have won't charge if the cord is in one orientation but fast charges in the other orientation.
It isn't. Either your cable is bad, or the port on your phone is bad/broken.
Symmetric is the default but not required by the standard, so directionality is permitted if irregular.
Technically cables are part double sided (USB3 wires, grounding) and part single sided (power, USB2), while ports should be double sided.
Clean it. fixed
![[HN] USB inventor explains why the connector was not designed to be reversible](https://radiation.party/pictrs/image/f307d45c-3fa2-4c83-b245-9ed4d88a4aef.jpeg?format=webp&thumbnail=196)
