Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

How many kinds of USB-C to USB-C cables are there?

people.kernel.org

Post reply on HN
Print view View original

81–90 of 210 posts

Re: How many kinds of USB-C to USB-C cables are there?

#81

Post by msbarnett »

Dylan16807 wrote: post #78
msbarnett wrote: post #69

Earlier quoted context omitted.

> Nobody else is complaining that the devices don't do everything. Tons of regular consumers think that USB-C is a protocol and frequently complain that things they think should work together don’t, because they’re actually radically different ports electrically that happen to be shaped the same. Gaming forums are rife with elaborate conspiracy theories behind why Nintendo won’t “just” release an eGPU Dock for the Sw…

> presumably the removed the DisplayPort crossbar IC that does alternate mode muxing with the USB 3.0 signal, to reduce manufacturing costs It probably saves some amount of money, but I'd bet that deliberately leaving it out to encourage sales of the full switch is a bigger factor. Otherwise I agree with you about protocol confusion. (Would you even need a mux? I don't think the switch uses USB 3 for anything.)

Yeah, you need the mux because you can run a wired Ethernet adapter in over USB at the same time it’s outputing a DisplayPort signal on the port.

Re: How many kinds of USB-C to USB-C cables are there?

#82

Post by Dylan16807 »

msbarnett wrote: post #81
Dylan16807 wrote: post #78

Earlier quoted context omitted.

> presumably the removed the DisplayPort crossbar IC that does alternate mode muxing with the USB 3.0 signal, to reduce manufacturing costs It probably saves some amount of money, but I'd bet that deliberately leaving it out to encourage sales of the full switch is a bigger factor. Otherwise I agree with you about protocol confusion. (Would you even need a mux? I don't think the switch uses USB 3 for anything.)

Yeah, you need the mux because you can run a wired Ethernet adapter in over USB at the same time it’s outputing a DisplayPort signal on the port.

That uses the USB 2.0 wires, as far as I can research.

And if it was using a mux to pick signals they wouldn't run at the same time anyway.

Re: How many kinds of USB-C to USB-C cables are there?

#83

Post by benj111 »

Really what were the USB guys thinking.

I had to 'fix' my inlaws computer today because some shovelware browser was autostarting, and had a banner across the top to change the autostart settings.

How am I supposed to communicate the finer points of USB-c USB 3 and all the various combinations to them, when I cant even keep track myself. USB was successful because it was plug and play, simple, easy to use. All the things USB3c isn't.

Re: How many kinds of USB-C to USB-C cables are there?

#84

Post by jasomill »

AnIdiotOnTheNet wrote: post #17
wmf wrote: post #6

Earlier quoted context omitted.

This is used for charging laptops. Personally, I love having a single cable for power, USB, and DisplayPort.

You ever wonder what the purpose of keying connectors is? I'm curious, because it's one of those time-tested ways to ensure that things get plugged into the correct ports and avoid costly accidents. Really simple too. Why on earth is a standard as ridiculously complicated as USB-C a better idea? What is the practical value of an "everything" connector when its spec is so complicated that it really doesn't support "ev…

Unfortunately, using identical connectors for incompatible protocols — often hazardously incompatible (to equipment) protocols — is an equally time-tested industry tradition, and not only in more cost-conscious market segments.

High-voltage differential SCSI comes immediately to mind — one might imagine there'd have been enough margin and price inelasticity in the market for $200 cables used to connect rooms full of $20,000+ storage devices to support the development and manufacture of slightly different connectors to prevent damage by connection to then-ubiquitous single-ended SCSI busses, but I suppose the projections for increased sales or reduced maintenance costs (for the vendors) due to redesigning the connector weren't high enough to justify a decision to standardize on different connectors for single-ended and differential SCSI.

Similarly, given that USB-C was essentially a fait accompli on the drawing board, short of material risk of injury or death due to misuse of otherwise compliant cables, I'm not convinced any one player in the industry — or any group of players likely to collaborate on something such as this — has both the means and the motive to seriously suggest something better.

Why build a better mousetrap when the world can't afford to beat a path away from your door?

Re: How many kinds of USB-C to USB-C cables are there?

#85

Post by beefalo »

derefr wrote: post #80
wongarsu wrote: post #74

Earlier quoted context omitted.

If a device has an HDMI port I know I can use that to connect a display. I don't know details like the supported resolutions, but at least I know that's a supported use case. If I notice that a device has a USB-C port all I really learned is that it has a USB-C port. Who knows what it does.

But that's most port standards that have ever existed. What can a device do with a parallel port? A serial port? A SCSI port? A Firewire port? Who knows? It's up to the device. It can certainly send signals over that port, of some kind. But what kind of signals? Up to the device. The host can hopefully probe a device-class out of the client and stand up an appropriate driver to talk to it. A CD player has a 3.5mm aud…

I think one of the things that makes USB-C particularly problematic here is that "plug it in and find out" can be harmful to devices since devices can draw 100W of power through the port.

Re: How many kinds of USB-C to USB-C cables are there?

#87

Post by msbarnett »

Dylan16807 wrote: post #82
msbarnett wrote: post #81

Earlier quoted context omitted.

Yeah, you need the mux because you can run a wired Ethernet adapter in over USB at the same time it’s outputing a DisplayPort signal on the port.

That uses the USB 2.0 wires, as far as I can research. And if it was using a mux to pick signals they wouldn't run at the same time anyway.

Well, I can tell you that it has a mux, anyways — it’s a Pericom PI3USB30532 per iFixit’s teardown. Exactly what for I don’t know.

Re: How many kinds of USB-C to USB-C cables are there?

#88

Post by krick »

falcolas wrote: post #31
shrimp_emoji wrote: post #19

Earlier quoted context omitted.

That or it's a spectacular example of committee design failure. I can't tell what runs deeper: evil or stupidity. :D

"Sufficiently advanced incompetence is indistinguishable from malice." I don't have an attribution, but it's an apt quote.

> I don't have an attribution

This is called "Hanlon's razor" and, by the way, it is probably a silliest, baseless, most overused saying on the Internet...

Re: How many kinds of USB-C to USB-C cables are there?

#89

Post by ajross »

jrochkind1 wrote: post #79
starsinspace wrote: post #42

After buying a screen which has only a USB-C DP-Alt-Mode input, I was recently in the market for a matching cable. My only requirements were “it should be as long as possible, at least 2 meters” and “it needs to support DP-Alt-Mode”. Now I thought this would be easy, just ask Google what kind of cable I need, right...? Well... no. Not at all. I wasn’t able to find any information whatsoever what kind of USB-C cable i…

Why don't they give NAMES to these different types of cables? They seem to have either no names or too many names where it's unclear what is intended for the consumer. Just giving the cable a clear name (in words, not icons), so you could know what you were buying, and a device could say "you need this kind of cable", and a person could write a blog saying "to support DP-Alt-Mode you need X kind of cable" and all use…

> Why don't they give NAMES to these different types of cables?

Exactly! We can call the one for small peripherals "USB", the one for monitors "VGA", the one for networking "ethernet", the one for power "AC"... I suspect most users can figure out how to manage that.

Snark aside, I actually agree with you. The market powers that be completely messed this up. Basically, phones have limited port space. And for their benefit, and only their benefit, we've tried to cram together the entirety of device I/O into one multi-pronged standard that was clearly never going to work.

And those phones? Their fancy USB-C ports are almost exclusively idle. A median high end phone never does anything with that port it couldn't have gotten with a single barrel connector with ~10V DC.

Re: How many kinds of USB-C to USB-C cables are there?

#90

Post by Dylan16807 »

msbarnett wrote: post #87
Dylan16807 wrote: post #82

Earlier quoted context omitted.

That uses the USB 2.0 wires, as far as I can research. And if it was using a mux to pick signals they wouldn't run at the same time anyway.

Well, I can tell you that it has a mux, anyways — it’s a Pericom PI3USB30532 per iFixit’s teardown. Exactly what for I don’t know.

That's fair.

Though presumably the switch lite doesn't need to support USB at all.

Post reply on HN