This is great for backwards compatibility, but can confuse users. You could have a TB3 drive attached to a TB3 computer by a USB cable with type C connectors that only operates at USB 2 speeds. It will silently fall back to a very slow transfer.
I don't know how the committee could have done much better though; this kind of fallback is important. Some mandated labeling would have helped a lot though.
From pictures on Amazon [0], a lot of cables being advertised as Type C USB3 are actually missing the 'SS' labelling, despite being advertised as 'Superspeed' (i.e. 5Gbps) in the description.
[0] https://www.amazon.co.uk/Anker-PowerLine-Durability-Devices-... - in this case, it currently provides a link "There is a newer version of this item" which links to a USB2 version(!).
Even a simple micro-USB on phones needed a pop-up to select what functionality the user wants to activate (charging, file transfer, host mode, debugging).
The problem is not new, but most software makers are stubborn miscreants that hate good UX (simplicity, discoverability, accessibility / introspectability, extendability). They usually champion one aspect to the total detriment of the others - eg GNOME3, phone OSes.
Why would it be silent? The computer would hopefully show a small notification that the transfer is happening slower than it would with a newer cable
If the computer can identify the device’s capabilities (using some kind of bus command, I’m not very familiar with the USB protocol) separately from speed testing the cable+device combination, no reason why it couldn’t work for USB 2/3/4.
Of course, this approach relies on the device accurately reporting its capabilities, which may not be the case for the more cheap-and-cheerful gadgets.
In fact, my ThinkPad X1 Yoga has two USB-C ports with Thunderbolt icons next to them. They support USB 3.1 Type-C Gen 2 with Thunderbolt 3 (including DisplayPort).
How many PCI-E lanes does each port get?
Do the ports share the channels/lanes?
Do they both support Power Delivery? How many Watts does the thinkpad need to charge?
Even with 'clear' labelling, it can still be a crapshot as to the full capabilities of the device.
Right now I have an Uptab Mini-DisplayPort adapter in one port, and a StarTech full size DisplayPort adapter in the other. The Uptab adapter has its own USB-C input for power, so that is where the power supply is connected.
The mini and full size DisplayPorts are each connected to a 4K monitor, and I use all three - the two externals and the ThinkPad's WQHD. This all works great when the Uptab is in the rearmost USB-C port and the StarTech is in the other port. But if I switch the two around, one of the monitors goes into low resolution mode!
This kludgy configuration is just because these were the adapters I had on hand. There are a number of adapters that plug into a USB-C port and give you two mini-DisplayPort outputs - I have been meaning to try one out.
And therein lies the problem.
Used to be, we could call a USB port a USB port. Everybody knew that if the computer had the port, it could work with the peripheral; if the computer didn't have the port, it would not work with the peripheral. If the peripheral required different functionality then it required a different port that was equally straightforward and obvious.
Now, it's all supposed to run over USB - at least, over some USB. Consumers go out and buy a device and then are confused when it doesn't work. They know their computer has a USB port, but that's not enough. The port no longer represents a definite protocol, or even a definite power supply capacity. Are they supposed to check to see whether each of their USB ports says "USB 3.1 Type-C Gen 2 with Thunderbolt 3 (including DisplayPort)" next to it (which it doesn't)?
That pin is supposed to use data signals of less than two volts. The nyko charger uses nine volts. The switch has no over-voltage protection on that pin, and breaks at more than six volts.
The part about a slightly thinner plug isn't relevant at all.
The only outliers are moronic implementations like Nintendo, where they ask for capabilities, receive the charger capabilities and then just start pulling power at hardcoded levels even if the charger doesn't specify it supports those power levels. But there's nothing you can do against that - you even with different port shape, a broken implementation can still fry your device.
I infer your point: the shape of the connector in theory is decoupled from risks in power delivery... but in reality the prevalence of cheap knockoffs and "moronic implementations" makes me question the wisdom of combining [potentially dangerous levels of] power delivery with data transfer.
Why would adapters necessarily not work in this case? It looks like you're claiming that translating one protocol to another is always impossible, but that can't actually be the idea... right?
In that case, you've described two situations:
1. Ports are the same.
2. Ports are different.
This doesn't seem like a particularly fruitful analysis.
The adapter is the downside. And there's no guarantee that the perfectly suitable adapter actually exists.
I disagree. The situations are:
1)ports are the same, protocol match : works
2)ports are the same, protocol mismatch : won't work, some user confusion
3)ports are different, protocol match : could work but won't without an adapter
4)ports are different, protocol mismatch : won't work. Adapters might exist but those won't work either.
I'd much rather deal with situation 2 over 3 and 4. Display adapters already have situations where you can get adapters to cobble together DVI and VGA ports but still fail to get a proper connection, so its not really a fix anyway.
The USB foundation should just come up with better branding around what kinds of things a port supports. No reason we can't have a thunderbolt icon next on a USB port. Its strictly better than a new physical port, IMO.