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Comment by dschuetz | Hacker News Reader

So where exactly does USB-C fall into?

I have 2 different generations of USB-C hosts, and they behave quite differently when approaching max cap, especially with high-quality low-latency audio (USB-C was supposed to be de-facto replacement for FireWire).

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USB-C is a connector type, like USB-A (usually known as the classic USB plug) and USB-B (usually the other side of said plug, a square kind of connector). USB-B had other offspring like miniUSB and microUSB (note that in these cases on the other side of the cable you usually have a USB-A plug).

USB-C is the first time cables have the same connector on both sides, so it obsoletes USB-A and USB-B. But what is sent over USB-C? Can be USB 3 with which it is often conflated because they came around the same time, but it can also be USB 2, so it is a bit hard to tell. But USB 3 can use old style USB-A as well (the blue plugs with the same shape as the classic USB plugs) and USB-C (the microUSB plugs with an extension off to the side).

Can be USB 3 [...] USB 2, so it is a bit hard to tell.

...or Thunderbolt, USB 4, DisplayPort (through Alt-mode or encapsulated in Thunderbolt), or HDMI (Alt-mode), or MHL (Alt-mode), USB Power Delivery...

Unfortunately, not every cable with USB-C connectors can carry all of these. E.g. there are USB-C cables that can only carry USB 2. Or cables that can carry USB 3, but not Thunderbolt. Also, not all cables can carry the same wattage for power delivery.

It's a mess.

Of course USB-C makes this worse, but the problem already started earlier: a few years ago I connected my phone to my computer with a USB-A to micro USB cable and was scratching my head why it didn't work. Then I remembered that the cable had come with some Bluetooth headphones and was only a charging cable without data lines...

Desktop speakers do this still. Instead of simply being a USB speaker set, they use the line out jack for audio and a USB plug for power.

There's actually a reason for that. Standard USB can (obviously) only transfer digital audio, and most speakers are "dumb" devices designed to just amplify an analog signal. In order to convert digital to analog, you need a DAC (Digital-to-Analog-Converter), and good DACs are still a nontrivial cost to a manufacturer, so whatever DAC you already have in your computer is probably better than the crappy one that would come with cheap consumer speakers.

Funny enough, USB-C can transport analogue audio over USB cable though :)

Tends to be too expensive for the cheapest of products.

There was a period of time where a google engineer was producting review on amazon about which usb-c cable would make your laptop burn. That was fun, and totally not the sign of an overbloated standard.

IIRC, that particular cable was one which had its power wired to the ground pin and ground wired to the power pin. No standard can help you if the cable is that badly made.

(The effect of that miswiring is to apply a negative voltage, around -5V, to a chip most probably designed for a range of -0.5V to 20.5V; which results in a short circuit through at least the ESD protection diodes within the chip, and possibly other parts of the chip too.)

Yep, a batch of cables having the super basic power pins wired backwards tells you basically nothing about the standard, no matter how often people try to use it as evidence of complication.

And the docks that were frying switches were putting 9 volts on a signal pin, also obviously wrong.

Worse, there are no "best" cables longer than 0.5m: any longer than that, Thunderbolt 3 requires active cables which don't pass non-Thunderbolt data beyond, IIRC, 480 Mbps.

As someone who spent many years using a mix of 25/50/68/80-pin fast/ultra/… single-ended, LVD and HVD parallel SCSI devices, however, USB-C/Thunderbolt cabling still feels like a breath of fresh air.

I think Thunderbolt 4 active cables are supposed to pass higher USB 3 speeds? At least the Apple Thunderbolt 4 cable claims to do so:

https://www.apple.com/shop/product/MN713AM/A/thunderbolt-4-p...

>note that in these cases on the other side of the cable you usually have a USB-A plug

Usually a full-size USB-A, you mean, because what we commonly know as mini-USB and micro-USB are actually mini-B and micro-B, which have corresponding (but now rarely used) micro-A and micro-A ports. Before USB-OTG, USB used to be an explicitly directional protocol, with a master and a slave device.

https://upload.wikimedia.org/wikipedia/commons/8/82/USB_2.0_...

https://en.wikipedia.org/wiki/USB_hardware

It's orthogonal.

Usb A is a host side connection Usb B (normal/mini/micro) is a client side connector Usb C is a 2 way connector.

Each of them can be implemented for each USB version, except USB C came later and makes no sense befor USB 3.

Then USB versions added features, signalling conventions and wires. But the USB A and B connector are backward compatible all the way to USB 1.0 1.5Mbit/s

On-the-Go allows mini and micro B to be host as well.

Good question. I bought a RaidSonic Icy Box IB-1121-C31 USB 3.1 (10Gbit) S-ATA dock recently (with a USB Type C connector) that came with a USB C cable and had a buy a special "USB-A - USB type C cable" to achieve 10Gbit/s with the 10GBit/s USB A connector of my mainboard.

The "USB A - USB type C cables" that i had already only worked up to 480MBit/s.

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