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USB inventor explains why the connector was not designed to be reversible (2019)

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Re: USB inventor explains why the connector was not designed to be reversible (2019)

#271

Post by Scoundreller »

JoblessWonder wrote: post #247
dylan604 wrote: post #207

Earlier quoted context omitted.

>edit: Gah! you don't even have to do that just flip the flipping wires) Isn't that essentially what all ethernet cables do? it's not like this something never done before.

When was Auto MDI-X introduced? A quick google failed to get me an answer but I remember USB being available while I still needed a crossover cable to hook up 2 switches.

oh god, I was made to be an idiot when I once told someone they would need a crossover cable to do what they wanted to do a few years ago...

Re: USB inventor explains why the connector was not designed to be reversible (2019)

#272

Post by sillywalk »

lesuorac wrote: post #13

I know everybody is still on the high from USB-C but I'm still going to go on the record it will be one of the biggest disasters in cable history. 1) There's going to be video-only cables; low-voltage only cables; etc and this time everything is usb-c so you can literally only tell which ables work by testing all of the dozen cables instead of the 1-2 USB-As you have. 2) The connector is symmetrical but the pins aren…

Not to mention the entire USB naming scheme.

USB 3 ? or 3x3 or 2x or ...with Thunderbolt or not...

Re: USB inventor explains why the connector was not designed to be reversible (2019)

#273

Post by nerpderp82 »

bigstrat2003 wrote: post #266
layer8 wrote: post #202

Earlier quoted context omitted.

The D-sub connectors were pretty intuitive, as far as I can remember. The 9-pin joystick ports never caused much trouble. Making the USB connectors symmetric in their outer shape but not symmetrically pluggable was really inexcusable. When it came out I remember thinking that it was worse than any of the existing connectors. And this is supposed to be the new “universal” connector?

> The D-sub connectors were pretty intuitive, as far as I can remember. I never personally had a problem with them, but I can attest that people did. At my first job (a small computer shop), we had multiple customers who tried to jam their D-sub connector on wrong, and broke one or more pins off. Since this was back in the day when the cable was hard wired into the monitor, that generally meant they had to buy a new…

That is malicious, you cut off the d-sub connector and put another one on. I have never heard of someone replacing a monitor because the pins on the connector were damaged.

Re: USB inventor explains why the connector was not designed to be reversible (2019)

#274

Post by userbinator »

kybernetikos wrote: post #250
snakeyjake wrote: post #140

> Making USB reversible to begin with would have necessitated twice as many wires and twice as many circuits, and would have doubled the cost. This is... not correct. You can make USB reversible with 1 extra pin and 1 extra wire. Grounds on pins 1 and 5, data on pins 2 and 4, and VCC on pin 3. Then have those pins on both sides of the plug and a socket with a single set of contacts on one side. That's BASICALLY what…

Couldn't original USB have used TRRS? That's better than reversible - an infinite number of orientations are allowed.

That shorts together a lot of the contacts as you're plugging it in.

There are of course various devices which somehow ended up using TRRS for USB, but unplugging/plugging those while powered is definitely not recommended:

https://www.reddit.com/r/ErgoMechKeyboards/comments/rt083u/a...

http://www.totekinternational.com/35mm-trrs-to-usb-a-male-ca...

https://pinoutguide.com/PortableDevices/ipod_shuffle_pinout....

Re: USB inventor explains why the connector was not designed to be reversible (2019)

#275

Post by Findecanor »

theogravity wrote: post #114

> Making USB reversible to begin with would have necessitated twice as many wires and twice as many circuits Is this still true with USB-C?

Reversibility for USB 2.0 data signals is mechanical: There are data pins on both sides and only one set of pins get connected. The socket side connects both sets.

There is only one more wire in a USB-C 2.0 cable: it is used to signal orientation and if an end is a power source, sink or a headphone adaptor.

USB-3 signals are more complicated though. There can be up to two bidirectional high-speed channels. The aforementioned sensing pin is used to figure out if those channels need to be swapped or not.

Re: USB inventor explains why the connector was not designed to be reversible (2019)

#276

Post by cesarb »

Izkata wrote: post #205
Ajedi32 wrote: post #160

Earlier quoted context omitted.

Yes, I have seen some products still using micro-B. I've generally just avoided them because I don't want to have to carry another type of cable, so maybe that's colored my perception a bit of how widespread USB-C usage is. For the products you've purchased that came with an A-to-C cable, have you tried using them with a plain C-to-C cable? In my experience usually that will "just work". (Maybe there are some power b…

Just tried plugging my phone into one of those power banks like that: The phone recognized it was plugged into USB, but didn't start charging. The light on the power bank did turn on though, so I redid it with a USB power meter: The power bank was sucking power from my phone at about 3.4 watts.

> The power bank was sucking power from my phone at about 3.4 watts.

At least on Android, there's an option to change the power direction (IIRC, it's in the same place where you choose the data connection mode). I have to use that option to switch the direction whenever I use the USB-C cable to charge my phone from my laptop, otherwise it tries to charge the laptop from the phone.

Re: USB inventor explains why the connector was not designed to be reversible (2019)

#277

Post by Smoosh »

stevage wrote: post #193
whoooooo123 wrote: post #190

Earlier quoted context omitted.

The problem with USB-a isn't that it's non reversible, it's that it's non-reversible _and_ rectangular, so it's not clear at a glance which way round it should go. All they had to do was make the connector have a non-symmetrical shape so that it's immediately obvious which way round it goes when you pick it up - you could do it without even looking. Think of how much time we'd have collectively saved with this minor…

Even having a bump on the rubber moulding as part of the standard would have solved the problem.

Heck, just making the plastic insert white instead of black (now sometimes blue, occasionally orange) would have helped.

Re: USB inventor explains why the connector was not designed to be reversible (2019)

#278

Post by hedora »

aranchelk wrote: post #164

My take on USB-A: aside from audio connectors that have axial symmetry (and have no meaningful orientation), I never used any reversible computer cables prior to USB-C, and that’s not the main issue. Nor is it the axis of symmetry of the casing allowing failed upside down plugin attempts. The shitty part of USB-A is that the tactile feedback of being slightly misaligned is identical to it being upside down. My experi…

The best feature of those little thumb screws was that the computer-side mount could become unscrewed and fall off when you were trying to remove the cable. On some machines, it was held in with a tiny little nut on the inside of the case. The nut was just the right size to fall onto a motherboard and bridge PCB traces or exposed I/O pins.

Of course, there was no way to detect this by feel.

Re: USB inventor explains why the connector was not designed to be reversible (2019)

#279

Post by snarfy »

I was always hoping for a 3.5mm jack for a connector.

Radially symmetric, it can go in any direction. I've heard arguments this could cause connection issues since it could rotate while connected, causing small contact misses, but I think that could be designed around.

Re: USB inventor explains why the connector was not designed to be reversible (2019)

#280

Post by JoblessWonder »

Scoundreller wrote: post #271
JoblessWonder wrote: post #247

Earlier quoted context omitted.

When was Auto MDI-X introduced? A quick google failed to get me an answer but I remember USB being available while I still needed a crossover cable to hook up 2 switches.

oh god, I was made to be an idiot when I once told someone they would need a crossover cable to do what they wanted to do a few years ago...

If it makes you feel any better... for some reason there are some currently in production business jets that still require crossover cables for maintenance... so they ARE still required sometimes.
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