Hacker News Reader

Comment by sackofmugs | Hacker News Reader

That's strange, I've never encountered a usb-c cable that did not support data at all. My understanding (and the article suggests) that charging and data are fine in general, but just not as fast as the device can support. Basically they will charge or transfer data at regular usb or micro-usb speeds.

View on HN

Ya, I found the answer on Apple's site:

https://support.apple.com/en-us/HT208368

> Compared with Apple USB-C Charge Cable The Apple USB-C Charge Cable is longer (2m) and also supports charging, but data-transfer speed is limited to 480Mbps (USB 2.0) and it doesn't support video. The Apple Thunderbolt 3 (USB-C) cable has Thunderbolt logo on the sleeve of each connector. Either cable can be used with the Apple USB-C Power Adapter.

I definitely have encountered this. One was even a device intended for development via USB. For some strange reason, the USB-C cable shipped with the product only supported power, requiring the customer to buy another cable for data transfer.

Just to clarify, are you talking about a usb-c to usb-a cable, or a usb-c to usb-c cable? I think the usb-c to usb-a cables are just temporary while we get to usb-c everything, and so are not implemented that well. With usb-c to usb-c cables, I've never had a problem with power or charging.

I’ve amassed quite a collection of charging-only Type-C to Type-C cables over the years. People usually don’t realize they have such cables because they typically come alongside a charger, so people only ever attempt to charge devices with them.

Grab a USB-C to USB-C cable that came with a phone or similar device and was intended for use with a USB-PD charger and give it a test. You might get USB 2.0 speeds if you’re lucky, but you’re unlikely to see anything beyond that.

nope, there are plenty of power only usb-c to usb-c cables.

Even more fun, many of them don't properly list what power they can handle and fry your device or catch fire if you put to much through them!

> Even more fun, many of them don't properly list what power they can handle and fry your device or catch fire if you put to much through them!

That doesn't make sense. Any cable will be capable of many more volts than USB will ever put through it. How is anything going to get fried?

I suppose a cable could get too warm, but lying about capacity only takes you from 3 to 5 amps. That little bit extra should never be enough to cause a fire. And if it can't even handle 3, then the problem was not that it was lying about capacity. It also costs extra money to lie about being a 5 amp cable since that requires a chip.

The only case I know of where a USB-C cable fried something, it was horribly broken. https://www.engadget.com/2016-02-03-benson-leung-chromebook-...

Volts don't melt power cables, amps do. Regular cables do 2.5 to 3A, the 5A cables are relatively rare and more expensive.

Yes, I know.

I mentioned volts for frying, and I mentioned amps for fire.

And I don't think either failure can be caused by a cable failing to properly list what it can handle. Do you?

It's crappy devices all around trying to implement an insanely complex spec.

The Nintendo Switch can get fried in dock mode (and Nintendo usually has pretty top notch QA/abuse testing outside of joysticks)

Here's a report of an A to C cable on fire from Anker (another pretty well regarded manufacturer) https://www.reddit.com/r/Android/comments/7j3k38/anker_usbc_...

Are you talking about the thing where sending 9 volts on a data pin fries the switch? I don't blame the spec or Nintendo for that one.

That cable is more of a complexity problem, but it wasn't because it misrepresented capabilities or anything. They put in a chip which didn't reset the connection when you unplugged one end. I don't know if that's really a spec problem, though.

The cable that comes with the Mac chargers is only a USB 2.0 + USB-C power delivery the cable and doesn’t support usb 3.0/3.1 data rates or TB.

USB type-C cables that support power delivery can have 2 ground pints, 4 VBUS (power) pins and 1 CC (cable connect/config channel) pin.

The first MacBook model with USB-C shipped with a USB 2.0 cable for its charger that only supported charging. I don't know if this is still true, though (I haven't checked the one that came with my newest one).

Do you have a source? I looked for a while and couldn't find anything except ones that say it supports data, just usb 2.0 speeds.

Found it here: https://support.apple.com/en-us/HT208368

Right, but it literally says there it supports data transfer. So it's not charging only.

I haven't seen one either but I can easily believe it, as there are proprietary magnetic USB-C adapters that do not support data (they only have 5 or 6 pins). I can imagine a "normal" cable behaving the same way.

Two pins for power, two pins for data, a pin or two for cable detection, what's the problem with that number of pins?

2 data pins is USB 1.X/2.X USB 3.X requires 6 data pins at a minimum.

USB type-C cables that only support charging will only have 5-8 pins 1-2 GND, 2-4 VBUS (power) and 1-2 CC (cable connect/config channel) pins.

The standard config for charge only cables (e.g. the Nintendo Switch charger) is 2-2-1.

> 2 data pins is USB 1.X/2.X USB 3.X requires 6 data pins at a minimum.

USB-C cables don't have to support 3.X to support data. You only need the two pins.

> The standard config for charge only cables (e.g. the Nintendo Switch charger) is 2-2-1.

That's a shame. It's really not that much effort to support 2.0 data.

I specifically bought a charge-only USB-C cable so I wouldn't have to worry about plugging my phone into an untrusted port to charge.

Reply on news.ycombinator.com