Some basic info about USB
Some basic info about USB
您正在查看单个线程.
273 留言
-
Additionally, USB 3.0, 3.1 and 3.2 labels provide no information on the speed. Rather, "Gen 1" means 5Gb/s, Gen 2 means 10 and Gen 2×2 means 20Gb/s. These "Gen" labels are seldom found on products however.
So for example USB 3.2 Gen 1 is 5Gb/s while USB 3.1 Gen 2 is 10Gb/s
-
The dear people at the USB Forum should be rewarded with the Nobel prize in namology for their clear, superior and non-confusing naming scheme and naming process that even the nerdiest of nerds can't follow.
-
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.
-
Behind the scenes, here’s what those labels correspond to:
- USB 5Gbps: USB 3.0 and 3.1 Gen 1
- USB 10Gbps: USB 3.1 Gen 2, 3.2 Gen 2×1, and 3.2 Gen 1×2
- USB 20Gbps: USB 3.2 Gen 2×2
- USB 40Gbps: USB4’s initial version as currently shipping
That's cool. But even though it finally adds simplicity, it's still yet another renaming of the same things.
Here's a snippet from an article from 2019:
The upcoming 20 Gb/s USB 3.2 connection, which offers twice the speeds of the previous iteration, will be known as 'USB 3.2 Gen 2x2'. Its predecessor, 'USB 3.1' will be rebranded to 'USB 3.2 Gen 2', while 'USB 3.0', which ran at 5 Gb/s speeds, will be termed 'USB 3.2 Gen 1'.
Reading that I want to shoot myself, and even the latest change, which probably is a good one, drives me slightly mad due to the history of renaming everything so many times.
-
the history of renaming everything so many times.
Every time a new USB spec comes out the version number goes up. A new spec comes out because they add more features. The spec is a whitepaper that explains all the features. It's a "The King is dead, long live the king!" situation.
If you just never used the version numbers to mean something that they never meant (transfer speeds) then literally none of this is confusing.
They've officially renamed the transfer speeds one time after people made a big huff. here's how they changed:
- USB SuperSpeed -> USB 5Gbps
- USB SuperSpeed 10Gbps -> USB 10Gbps
- USB SuperSpeed 20Gpbs -> USB 20Gbps
And If you can't follow along with that, I'm really, really sorry. There's not much I can do from a internet discussion board. XD
-
Yes, I am the only one confused. It's not like half the tech internet blew a gasket over how confusing and bad the renaming of the generations were. Just me. I guess I should just read the whitepapers of every standard going forward, silly me.
-
Well if there's anything I expect from the new-cycle masses, it's rationality.
Heaven forbid, we try and do better!
I guess I should just read the whitepapers of every standard going forward, silly me.
You don't have to read whitepapers to know the difference between Ethernet, CAT6 and RJ45 even if your grandpa doesn't know the difference.
It's not too much to expct the "nerds" to know the real names of PAN connections, too.
-
I aspire to be as cool as you.
-
-
-
clear text labels
The problem with using English anything is that while English is the most-widely-used language in the world, there are still a lot of people out there who don't know it.
The US has a history of just using English text for everything, because most people in the US can do English. Over in Europe, where the language situation is more-fragmented, I think that there's more push for using symbols, which...can have benefits, though it also means that everyone has to learn some symbols.
Maybe "STOP" or "ON" and "OFF" or something aren't that hard to learn. My gut is that maybe we could expect just about everyone in the world to learn a super-minimal subset of English using all-capital Latin letters or something for labeling purposes. "ON", "OFF", "STOP", "YES", "NO", "CANCEL", "POWER", "ERROR", "RESET", "UP", "DOWN", maybe something along those lines. Kinda like a pidgin English designed for devices. But that thing has "CERTIFIED", hardly the first thing someone learns. Also, it appears to have built a US trademark indicator and registered trademark indicator into various official labels, which I think is kind of funny. Like, if the USB guys go out and alter the registration status of their trademarks, are they gonna change the labels, and is everyone gonna go alter their plastic molds and whatever?
Imagine all that text was a bunch of Chinese and imagine how palatable that'd be for the US market. Okay, it's easier to learn the (small) Latin alphabet than Chinese characters, which maybe makes learning basic words easier, but I can't recognize a single Chinese character.
I mean, don't get me wrong. I speak English. I'd rather have descriptive English than a bunch of obscure and sometimes similar-looking symbols, myself. But I don't feel like this is all that ideal, either, not from a global standpoint.
-
-
-
All so sales people can slap on a 3.2 sticker over the 3.1 that was on top of the 3.0 sticker...
-
Do people care? You just plug in your thing and it works, fast enough in most of the cases.
-
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 -- permits 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 -tto show the negotiated speed between two devices, so can use them to infer the speed, as long as you have fast-enough devices at both ends of the cable.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 understand that that software doesn't work on all Android hardware.
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 unplug them and plug them in again to get transfer 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.
-
I'd also add that while I have rarely had problems with it -- only came up with one USB-powered analog audio mixer that had less-than-amazing power circuitry and bled noise from dirty power being provided by USB through into the audio signal, and where I put it on a dedicated charger -- USB power can be stupendously dirty. I was watching some guy with an oscilloscope investigate various devices, and all those sensitive devices are accepting all kinds of craziness in terms of power. I'm surprised that USB power sources aren't required to provide some hard guarantees on what they can do in terms of load and response.
-
-
-
Additionally, USB 3.0, 3.1 and 3.2 labels provide no information on the speed
Correct.
USB X.X is the name of the technical whitepaper that describes the standard.
For a long time, USB had three transfer rates. The first legacy speed (slowest) was hardly ever used. The Second was called "Full Speed" and the fastest was called "Hi-speed". Because people could not remember which if these two were faster, they referred to the whitepapers in which they were introduced.
When later versions of USB were introduced people have tried to continue this mental "shortcut" and have caused themselves nothing but confusion.
-
273 留言