If you have a 3.0 port on one device, a 2.0 port on the other device, and a 3.1 cable, you get 2.0 transfer speeds.

USB ports are not labeled with numbers. You just made up numbers to name several different things.

This is why you think things are “poorly labled”. Your headcannon is broken, not the labeling.

Same with my keyboard, and I appreciate the compatibility. If it doesn’t need anything faster than 2.0 speeds, there’s no reason to include more expensive parts.

It’s also important to permit use of adapters for backwards compatibility. Like, if we stop having computers with A ports, there are still gonna be some very expensive devices out there that have A ports. You aren’t going to throw out your electron microscope with a USB A port because the USB guys have decided that USB-C being reversible is cool.

I find it hilarious that Apple did that with the iPhone 15. Gave the current technology to only the pro models 😂

They are such grimy bastards I swear, probably saved $1 just to make you pic the pro

My headphones (Sennheiser Momentum 4) have Bluetooth support. When using Bluetooth mode with the latest firmware update, they sporadically shut down while using in Bluetooth Multipoint mode.

I used headphones for decades very happily with a 1/8th inch jack.

They weren’t perfect.

• Some devices used a 1/4 inch jack. This at least was electrically-compatible, so one just needed a cheap, appropriately-shaped piece of metal to adapt them.

• The 1/8th inch jack connector took up enough space that the smartphone guys eventually mostly banished it from phones, to try to get a bit more space in the device.

• There wasn’t a standard impedance. While most consumer devices used more-or-less the same impedance (and if you had to, you could just adjust the volume up or down slightly with different headphones) some higher-end headphones required a headphones amplifier that could push more power.

• When you plugged a device in, it briefly shorted the connector, and made a lot of noise.

• It wasn’t wireless (which could be seen as a minus or plus, depending upon whether you wanted ability to walk away from a computer).

• It couldn’t transmit power (well, not much; there was a convention for doing so that didn’t become widespread). That became more significant with the rise of headphones with active noise cancellation, which would need at least some way to get power to the headphones.

But honestly, those were mostly pretty minor problems. Headphones just worked in virtually all cases.

I didn’t have to worry about whether-or-not my headphones supported a given sampling rate, the number of devices that could connect to my headphones, wireless interference, or physical plug compatibility aside from the 1/8th inch and 1/4 inch issue (well, and occasionally 2.5mm headset connectors on phones). USB audio didn’t resolve the calibrated volume issue, one of the few annoyances I had with the analog connector. I have one set of Bluetooth headphones that start breaking up when I leave the room with the transceiver and another that work flawlessly across the house. I have charging rates to worry about, and whether the device is smart enough to have a battery management system capable of prolonging battery life by shutting off charging at appropriate points. The protocol and physical connector for telephone jacks has changed twice over the past several hundred years, once to add a ring (for stereo) and once to move from 1/4 inch to 1/8th inch. The Bluetooth and USB standards, while providing for some level of backwards compatibility, have changed like some people change socks. There are different audio protocols (and in some cases competing audio codecs, like LDAC vs aptX). Lossy compression becomes an issue with Bluetooth. Some devices don’t support some sampling rates; analog headphones don’t care. Having (effectively) zero-latency pass-through mixing is guaranteed doable with any analog headphones with the appropriate mixer, so that one can hear some other audio source live; that’s not an option with Bluetooth or USB headphones.

I do like active noise cancellation, and occasionally the wireless functionality can occasionally be handy (though in general, it isn’t a game-changer for me). But I feel like the user experience has gotten a lot more problematic, in general.

Many expensive ones too. The iPhone 15 runs at USB 2.0 speeds, despite having USB-C.

One of those cables that don’t work is rated for like 120W, with gigabit transfer speed… But it refuses to transmit display… Like bruh

This has already been fixed by the forum FYI, the new spec is to just put clear text labels that denote the capability of the port. I can’t find the article I read but this one has an example of the new user-facing branding.

https://tidbits.com/2022/09/29/usb-simplifies-branding/

Why can’t I tether my phone to my laptop with two out of three of my cables?

I have an Android phone with a USB-C port and a laptop with (several) USB-C ports.

I have three cables that I carry with me: a USB-C-to-USB-C cable, a second USB-C-to-USB-C cable, and a USB-A-to-USB-C cable. None of these are charging-only power cables, and I’ve used them for data connections.

One of the USB-C-to-USB-C – an unmarked cable – doesn’t permit for USB tethering to be used.

The other two do not.

The other USB-C-to-USB-C cable even has USB 3.1 symbol.

I don’t know why.

Looking more-closely, it looks like the other two don’t have a data connection established between the Android phone and the laptop from the laptop’s perspective. They’ve let me do so with other devices.

Checking what data transfer rates a given cable supports electrically

As far as I can tell, there isn’t a way to query the “e-marker” on a USB cable from Linux today; I found a comment from someone saying that kernel support is still being worked on. You can use lsusb -t to show the negotiated speed between two devices, so can use them to infer the speed.

https://lemmy.world/post/18014298

What USB PD rates does a USB cable or power consumer or charger support?

I don’t know of a good way to determine this from a user standpoint. Note that this is a matrix of voltages and currents, so it isn’t just “I support up to rate X”. Also, not all devices display the rate of power that they are providing or consuming – in fact, most don’t. My Android phone, a reasonably-sophisticated device and one with a display and capable of both providing or consuming power, doesn’t show the rate of power consumption or provision, just “slow” or “fast”, without additional software.

I have – had – a laptop that just won’t charge if a charger doesn’t support a certain USB PD profile, which its provided charger did but not all charging devices did.

When I plug in two devices that both support USB PD, which is the consumer and which the provider?

When I’m in my car, I typically I have three devices that have USB PD ports and can either provide or consume power – a large powerstation, a laptop, and a phone. I eventually learned a few facts:

First, the direction in which power is being provided via USB PD is independent of which device is operating as a USB host or device using USB OTG ports; it’s possible for the direction to be different from the direction of power provision.

Second, apparently the direction of host/device order is random, and devices just remember the host/device direction for a certain amount of time, so that if you plug two USB OTG devices into each other and the direction is not what you want, the idea is that you can figure it out from one or more of the devices indicating this and then plug them in in the other direction.

Third, as best I can tell empirically, USB PD does the same random thing.

This creates all kinds of fun if one device powers off and then on again or something; my laptop can start draining its power to my powerstation (generally not what I want), or my phone to my laptop, since all the USB PD ports in question support USB PD in both directions.

Which end is which on an active USB cable?

I have an active optical USB cable, which I obtained so that I could put my computer in a closet, a long way from the rest of my devices; USB on copper has very limited range at present-day speeds without a repeater. It functions in only one direction in terms of data transfer (and obviously can’t move power). That particular manufacturer labeled it, though there’s no standard for labeling that.

In sum

USB does have reasonably good fallback, so most cables and most devices tend to sort of do something to some degree – they move some amount of power and some rate of data, though some devices have hard demands on what they need and there isn’t a great way to assess what a cable or device supports in most cases from an end user standpoint. But it definitely could be a lot better from my standpoint.

So do like they did for video and out 2A @ 5V. Now you have power.