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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)

#501

Post by ilyt »

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…

You have to consider that initially it was supposed to be connector for stuff like mouses or keyboards or gamepads or printers. 12Mbits.

But yeah that was only one of many misdesigns along the way. Like making turning ports on and off optional features, mini-usb (seriously, none other usb version I've seen failed as often as mini-usb connectors), just how overcomplicated USB-PD is, or the recent mess in USB-C cabling.

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

#502

Post by ilyt »

rusk wrote: post #413
musicale wrote: post #411

Earlier quoted context omitted.

PCgamer: > Incidentally, the late Steve Jobs deserves a tip-of-the-hat for helping USB become a long-lasting standard. It was in 1998 that USB made some real headway, courtesy of the iMac G3, the first computer to ship with only USB ports for external devices (there were no serial or parallel ports). That came three years after USB 1.0 debuted, with a data rate of 12Mbps. Also PCgamer: > Given that it was a protocol…

> the first computer to ship with only USB ports I remember presenting this in a project as an undergraduate and I was challenged by the lecturer that it would be highly unusual for a consumer device to ship without RS232 and I could only say “yeah”

To be fair for very long time most motherboards had RS232 port on headers, just not on back plate.

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

#503

Post by ilyt »

userbinator wrote: post #364
gzalo wrote: post #157

Earlier quoted context omitted.

> Then you implement auto crossover detection, dwhich had been around for years Mdi-x/auto crossover for ethernet was introduced in 1999, that is after USB (1996) was designed, not sure of the technique was known at that time

You can't do "auto crossover" with USB because it needs to distinguish between D+/D- for speed selection. https://electronics.stackexchange.com/questions/73295/in-a-u... It works for Ethernet because the transmit and receive lanes are separate, but with USB, there's only one pair used for both directions.

It doesn't need to.

It chose to. They could just use different way to do it. Like, I dunno, a single packet of negotiation in slow mode...

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

#504

Post by ilyt »

lttlrck wrote: post #340
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…

Right, don't make a non-reversible connector appear reversible... I would have thought this is Connector 101. It's so bad it takes me 3 attempts to plug in USB-A blind, at least 50% of the time.

other part of connector 101 is "put the springy bit on the cable, not socket, so when it wears out you replace a cable, not connector"

Given how Mini-USB looked I'm gotta say nobody there had any clue about designing connectors...

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

#505

Post by ilyt »

dheera wrote: post #386
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…

Or just put + and - through a rectifier and you don't need an extra pin. Data lines -- use differential signalling and polarity determined by whether +/- got reversed by the rectifier or not. Or do like Comcast does and put all bidirectional data through 1 conductor at multi-gigabit speeds.

Maybe if you have no clue about electronics don't talk about electronics...

> Or do like Comcast does and put all bidirectional data through 1 conductor at multi-gigabit speeds.

And how much modem's transceiver cost ? And how does that compare to cost of computer mouse or other cheap USB peripherals.

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

#506

Post by smoldesu »

scarface_74 wrote: post #366
Max-q wrote: post #358

Earlier quoted context omitted.

4) A USB 2 cable with USB-C in both ends can't 60W.

And this is kind of the point, if HN commenters can’t figure this stuff out, what are the chances that normal people can? Speaking of which, every time I ask the question about “tell me just from looking at a USB C cord…”, I learn something new.

> if HN commenters can’t figure this stuff out, what are the chances that normal people can?

Plugging it in would probably be a good start. I can't name a single time where I've ever mistakenly identified a USB-C cable. Sometimes I've plugged it in when it wasn't connected to the wall, but I think worrying about non-compliant USB-C cables is no more relevant than caring about non-MFI certified Lightning cables.

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

#507

Post by ilyt »

oblio wrote: post #391
cyberax wrote: post #314

Earlier quoted context omitted.

That's incorrect. USB-C design maximizes the device longevity by removing springs from the device that typically get worn down quickly. The cable is responsible for the grip. You do get a protruding tongue on the device side, but it's well protected.

I broke mine on a S21. It's also getting wobbly on 2 Essential Phones. As OP said, now those 3 expensive devices are mostly broken or at risk instead of the cheap cable. It's bad design compared to the Lightning connector, and I don't like Apple...

My OnePlus 5T have 4 years now and connector is still fine. I suspect user error

>Tt's bad design compared to the Lightning connector, and I don't like Apple...

Lightning connector is significantly worse.

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

#508

Post by bigstrat2003 »

nerpderp82 wrote: post #492
bigstrat2003 wrote: post #287

Earlier quoted context omitted.

I've never heard of anyone replacing their hard wired monitor cable. And in any case I certainly wouldn't have had the skills, so I think "malicious" is an uncalled-for term here. Maybe my boss (the owner) knew better and chose to charge people for new monitors, but I definitely didn't.

As a repair shop, it is your job to repair the broken thing, not just sell them a new one. A big shielded molded cable can be fixed, either at the connector or replacing the whole cable where it terminates into the PCB. If I had known about a shop disposing of 500-700$ monitors with bad cables, I would have made a fortune.

As I have said, I had no idea you could fix such a thing. Hell I didn't even know that until this very thread, much less 20 years ago. As such it was not in the least malicious (ignorant perhaps, but that's a separate thing).

In any case, your unfounded criticism of my moral character is really irrelevant to the main point I made: it was totally possible to fuck up plugging in D-sub connectors, and I witnessed multiple people who had done so.

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

#509

Post by Suppafly »

rzzzt wrote: post #200
stevage wrote: post #193

Earlier quoted context omitted.

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

The USB symbol goes on top, IIRC. Edit: ninja'd by an enormous amount of people elsewhere in the thread, gah.

It doesn't help if you've trying to do it totally blind, but the 2 open square holes go on top, once I figured that out I've never had any issues plugging them in correctly. The only one I have issues with is my keyboard because the pcb in the plug is black and the it's a little hard to tell which side is the open holes and which side is the black pcb.

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

#510

Post by scarface_74 »

smoldesu wrote: post #506
scarface_74 wrote: post #366

Earlier quoted context omitted.

And this is kind of the point, if HN commenters can’t figure this stuff out, what are the chances that normal people can? Speaking of which, every time I ask the question about “tell me just from looking at a USB C cord…”, I learn something new.

> if HN commenters can’t figure this stuff out, what are the chances that normal people can? Plugging it in would probably be a good start. I can't name a single time where I've ever mistakenly identified a USB-C cable. Sometimes I've plugged it in when it wasn't connected to the wall, but I think worrying about non-compliant USB-C cables is no more relevant than caring about non-MFI certified Lightning cables.

Until you take a USB C cable with you in your laptop bag to connect with your portable USB C external monitor that gets power and video from one USB C cable and find out you have the wrong USB C cable with you.
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