The USB "standard" is decending into chaos

[Saul Goodman]

There's consistently an A type on one end and a B type on the other, except when there's not, so that it's always clear to the consumer what's going on. This way the consumer can always know when they have got a non-standard setup and be clear that they now need to be slightly confused. This avoids uncertainty. Of course now with the C type connectors, sometimes on both ends and sometimes on both, and an array of slightly different speed standards, consumer confusion can be further standardised to be constant in all situations. It's amazing work.

Most of us just plug in a cable and it works. Maybe you should take a course in plugging in cables.

 

[teuchter]

I'm not an expert on this, so treat with some caution.

View attachment 260003

This is what's going on in a USB C connector. For a start, it's only half as complicated as it looks. As you can see, it's symmetrical, which is why you can plug it in either way up.

Lilac is USB 2.0 and in theory you could have a USB C cable with just four pins (two USB 2.0, one +V and one GND) in one row wired up and it would do the job of USB 2.0 only. Double that to make it work either way up.

Connect up the blues and you have support for USB 3.x data, despite what the legend says.

The yellow (CC) is used to negotiate the specific mode for USB 3.x which determines the speed but that's just a channel, not a job of the cable itself.

So, if you have a cable (or cable chain including adapter etc) where everything is properly wired up, then the cable should be irrelevant to the speed outcome, and it's down to what the devices at either end negotiate.

Thanks.

If I look at the pin diagram for a USB type A connector it just has 4 pins... so it's clear that if my cable chain has a type A connector somewhere in it, then even if it has type C at both ends it's not possible for all the pins to talk end to end.

What's a bit of a mystery to me is in what way one USB-C to USB-C cable might differ from another. Because the suggestion seems to be that they aren't all the same. Is it that not all of the pins are necessarily connected to anything? Or are there more things going on like impedance and other stuff I only very vaguely understand. It would be good to know what to ask for, for a cover-all USBC to USBC cable, if such a thing exists. It seems like maybe anything described as a Thunderbolt 3 cable might be that.

 

[mauvais]

Thanks.

If I look at the pin diagram for a USB type A connector it just has 4 pins... so it's clear that if my cable chain has a type A connector somewhere in it, then even if it has type C at both ends it's not possible for all the pins to talk end to end.

What's a bit of a mystery to me is in what way one USB-C to USB-C cable might differ from another. Because the suggestion seems to be that they aren't all the same. Is it that not all of the pins are necessarily connected to anything? Or are there more things going on like impedance and other stuff I only very vaguely understand. It would be good to know what to ask for, for a cover-all USBC to USBC cable, if such a thing exists. It seems like maybe anything described as a Thunderbolt 3 cable might be that.

The Wiki page for this is quite comprehensive if a little impenetrable.

USB-C - Wikipedia

en.wikipedia.org

Basically both of the things you said - improper impedance on one of the control channels, and just not being connected up for all the possible features.

 

[mauvais]

Thanks.

If I look at the pin diagram for a USB type A connector it just has 4 pins...

A USB 2.0 type A connector has four but a 3.x one, which is physically compatible, has more.

USB 3 Pinout (Type A and Type B). Signals and wire colors

www.aggsoft.com

 

[nick]

The advantage of USBC is that it is orientation agnostic. .....

Absolute monster builds 'cursed' USB-C port that works differently if you flip the cable

You thought your cable-flipping nightmares were over with USB-C. You were wrong.

www.pcgamer.com

 

[teuchter]

The advantage of USBC is that it is orientation agnostic. .....

Absolute monster builds 'cursed' USB-C port that works differently if you flip the cable

You thought your cable-flipping nightmares were over with USB-C. You were wrong.

www.pcgamer.com

In de Groot's hands, USB-C is like a mouse with only one button. Or a toilet paper holder that only rolls under, not over.

It's not like either of those things.

 

[Saul Goodman]

The advantage of USBC is that it is orientation agnostic. .....

Absolute monster builds 'cursed' USB-C port that works differently if you flip the cable

You thought your cable-flipping nightmares were over with USB-C. You were wrong.

www.pcgamer.com

Same as painting one side of the plug green and the other red... Fucking pointless.

 

[UnderOpenSky]

So I should know this, but don't care enough. Well until I need to buy one.

I've recently got a scanner that uses USB C for both power and data. It comes with various warnings that you need to use the special cable, which is clearly rubbish. However, I need a longer one than was supplied. Is there a special part of the spec to search for to ensure they deliver enough power? Or does it not matter as it can be powered by a computer USB3 port so can't draw that much?

 

[glitch hiker]

How about a standard where, whichever way I pick the cable up and proceed to plug it in, I invariably pick the wrong way

 

[UnderOpenSky]

How about a standard where, whichever way I pick the cable up and proceed to plug it in, I invariably pick the wrong way

I think that's called USB

 

[teuchter]

So I should know this, but don't care enough. Well until I need to buy one.

I've recently got a scanner that uses USB C for both power and data. It comes with various warnings that you need to use the special cable, which is clearly rubbish. However, I need a longer one than was supplied. Is there a special part of the spec to search for to ensure they deliver enough power? Or does it not matter as it can be powered by a computer USB3 port so can't draw that much?

It's quite easy to find out - just follow this flow chart



And don't forget to cross reference with this one:

 

[Saul Goodman]

So I should know this, but don't care enough. Well until I need to buy one.

I've recently got a scanner that uses USB C for both power and data. It comes with various warnings that you need to use the special cable, which is clearly rubbish. However, I need a longer one than was supplied. Is there a special part of the spec to search for to ensure they deliver enough power? Or does it not matter as it can be powered by a computer USB3 port so can't draw that much?

Look for a fast charging cable. Anker do good ones.

 

[existentialist]

I think that's called USB

But not USB-C....

 

[NoXion]

So I should know this, but don't care enough. Well until I need to buy one.

I've recently got a scanner that uses USB C for both power and data. It comes with various warnings that you need to use the special cable, which is clearly rubbish. However, I need a longer one than was supplied. Is there a special part of the spec to search for to ensure they deliver enough power? Or does it not matter as it can be powered by a computer USB3 port so can't draw that much?

Is the scanner's USB cable its only source of power, and is it meant to be plugged directly into your computer? Because if the answer is yes to both, then the 5 volts provided by the computer's USB port should be enough.

 

[UnderOpenSky]

Is the scanner's USB cable its only source of power, and is it meant to be plugged directly into your computer? Because if the answer is yes to both, then the 5 volts provided by the computer's USB port should be enough.

Yes. So am I overthinking it and pretty much any cable will do as a USB port can't supply that much power anyway?

Although obviously, it needs to carry data as well. I've not actually had a type c yet that won't but have heard they exist.

 

[NoXion]

Yes. So am I overthinking it and pretty much any cable will do as a USB port can't supply that much power anyway?

Although obviously, it needs to carry data as well. I've not actually had a type c yet that won't but have heard they exist.

USB cables have always carried both data and power in my experience. I think it's the port, rather than the cable, which determines that.

 

[Saul Goodman]

USB cables have always carried both data and power in my experience. I think it's the port, rather than the cable, which determines that.

I've come across some that only carry power. Granted, they either came with a device or from a dodgy ebay seller.

 

[existentialist]

I've come across some that only carry power. Granted, they either came with a device or from a dodgy ebay seller.

It is extremely frustrating when you discover one of those, especially if you have been tearing your hear out trying to diagnose a driver problem because the data lines weren't connected

I bin them when I find them now...

 

[Saul Goodman]

It is extremely frustrating when you discover one of those, especially if you have been tearing your hear out trying to diagnose a driver problem because the data lines weren't connected

I bin them when I find them now...

Almost as frustrating as the cheap ones with half a micron of copper in them. They might work on one device but fail on another, and it's always at a time when you really need a decent cable.
Again, I bin them, but they're like the proverbial bad penny.

 

[salem]

I've come across some that only carry power. Granted, they either came with a device or from a dodgy ebay seller.

That's a USB condom - useful when charging up from dodgy public USB ports that you don't want interacting with your data

 

[NoXion]

That's a USB condom - useful when charging up from dodgy public USB ports that you don't want interacting with your data

The public USB ports I've seen have all been power-only, for charging mobile devices on while the bus and so on. Where are these public USB ports with data capability?

 

[beesonthewhatnow]

The public USB ports I've seen have all been power-only, for charging mobile devices on while the bus and so on. Where are these public USB ports with data capability?

That’s the point - you potentially wouldn’t know, a dodgy setup somewhere could be used for nefarious purposes.

 

[glitch hiker]

It's quite easy to find out - just follow this flow chart

View attachment 282944

And don't forget to cross reference with this one:

View attachment 282945

The best part is that you can't even open the images to zoom in, so this could be a spell to awaken the dead for all we know

 

[NoXion]

That’s the point - you potentially wouldn’t know, a dodgy setup somewhere could be used for nefarious purposes.

Doesn't the device need the user to acknowledge the data connection in order for this to work? When I plug my phone into anything data-capable, it's pretty damn obvious; the phone tells me.

If not, then that's fucking awful security design. The user should always be made aware whenever a connection is made.

 

[beesonthewhatnow]

Doesn't the device need the user to acknowledge the data connection in order for this to work? When I plug my phone into anything data-capable, it's pretty damn obvious; the phone tells me.

If not, then that's fucking awful security design. The user should always be made aware whenever a connection is made.

I’ve no idea, but given the advanced level and complexity of various cyber attacks nowadays I’d assume some clever bastard has worked out a way around such measures.

 

[NoXion]

I’ve no idea, but given the advanced level and complexity of various cyber attacks nowadays I’d assume some clever bastard has worked out a way around such measures.

I'm pretty sure that they can't prevent your device from telling you a connection has been made, unless your device is already compromised.

 

[Saul Goodman]

Doesn't the device need the user to acknowledge the data connection in order for this to work? When I plug my phone into anything data-capable, it's pretty damn obvious; the phone tells me.

If not, then that's fucking awful security design. The user should always be made aware whenever a connection is made.

Yes, as far as I'm aware all phones do that. Although I can't speak for Apple .

 

[two sheds]

Have we had this?

 

[UnderOpenSky]

My new laptop charges from USB and also connects to an external monitor via it. Doesn't matter which port you use for either. I knew was a thing, but it's still pretty awesome.

 

[platinumsage]

My new laptop charges from USB and also connects to an external monitor via it. Doesn't matter which port you use for either. I knew was a thing, but it's still pretty awesome.

None of my monitors have USB inputs, just VGA, DVI, HDMI and DisplayPort