Hacker News new | ask | show | jobs
by Arnt 3783 days ago
Right... but two questions stick their head up and want answers:

First, USB outlets are supposed to have a bit of a fuse. Why was this upfuckage so spectacular?

Second, why do USB type C ports/cables have 24 pins if there are only 4 wires? I can understand having a couple of extra ones for type/orientation detection and a doubling to support reversion, but 24 is a lot.
4 comments
zyxley 3783 days ago
> Why was this upfuckage so spectacular?

Because it had power wired to ground. This would be incredibly absurd in ANY variety of powered cable.

This is not merely "noncompliant with spec", it's "actively dangerous because it could start a fire and kill somebody".

link
Arnt 3783 days ago
I see. Of course it would be very difficult to defend against that. Thanks.
link
mikeash 3783 days ago
I don't know exactly why these ports aren't protected, but as for your second question, why assume there are only four wires, given there are a lot more pins? Wikipedia has a full pinout and wiring list and you can see there's a lot more going on than that:

https://en.wikipedia.org/wiki/USB_Type-C#Connector_pinouts_a...

USB-C is not merely a new connector for the old USB 2.0, but includes a lot more. It is backwards compatible, but goes well beyond that.

link
Arnt 3783 days ago
Why assume that, indeed. The salesman who sold me my lovely new macbook told me (when I said something skeptical about quick charging via a thin cable).

Feel free to vote me down for believing something a salesman said.

link
mikeash 3783 days ago
That'll learn ya.

(For the record, I didn't downvote.)

link
Vendan 3783 days ago
well, usb type C is supposed to have at least 9 wires, if I recall correctly. This is not a valid type C cable, but it was being sold as one, which is part of the outrage. (aside from the "killing devices" bit)
link
cesarb 3783 days ago
A "USB Type-C to USB 2.0 Type-A cable" has 4 wires (same as any USB 2.0 cable, really; only the plug in one end is different).

The problem is that this was being sold as a "USB Type-C to USB 3.1 Type-A cable", which is supposed to have 10 wires.

(A full USB Type-C cable has some 18 wires, since it wires both sides separately so the alternate modes which use both sides separately can work.)

link
yincrash 3783 days ago
I'm not sure any spec for a power cable protects against switching V+ with ground.
link