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USB Cheat Sheet

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Re: USB Cheat Sheet

#21

Post by hyperman1 »

dschuetz wrote: post #19

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).

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

Re: USB Cheat Sheet

#22

Post by 0xTJ »

Just how much do you have to hate consumers to come up with a scheme like this? Increment revisions as you add more features, add something to the end to say how fast it goes. The 3.2 renaming is idiotic.

Re: USB Cheat Sheet

#23

Post by LeonidasXIV »

dschuetz wrote: post #19

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).

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).

Re: USB Cheat Sheet

#24

Post by _joel »

I've definitely used 5m+ extensions on USB1 (and 2 iirc) before. I guess it'd be sketchy running something that requires decent throughput and not b0rk on ECC/FEC/whatever it uses but for temperature sensors which I was using, it was fine.

Re: USB Cheat Sheet

#26

Post by CamperBob2 »

masklinn wrote: post #10

Some of the entries seem incorrect: "USB 3.2 (USB 3.2 Gen 2x2) and "USB 4" (USB 4 USB4 Gen 2×2) should have the same nominal data rate of 2500MB/s, they're 2 lanes (x2) of 10GB/s. Though they are apparently coded differently electrically, so they're distinct protocols. The tables would benefit from mentioning the coding (8/10 or 128/132) as IMO it's one of the most confusing bits when you see the effective data rates…

He goes off the rails earlier than that, by saying that USB 2.0 is "also known as" Hi-speed. HS is only one data rate supported by the USB 2.0 standard; it incorporates both full speed from the earlier standard and low speed, which isn't mentioned at all.

Re: USB Cheat Sheet

#27

Post by CoastalCoder »

can16358p wrote: post #20

So on the next versions of USB, the cable length will get shorter and shorter until the max gets to 5cm? While I get the technical reasoning about high frequency/attenuation etc that limits cable length as speeds go higher, there are obviously some practical limits to how short cables can be. How would that be solved, I don't know.

Not my area of expertise, but maybe some (unrealistic) options include using fiber optics for the data lines, or adding more data lines.

Re: USB Cheat Sheet

#30

Post by ThreePinkApples »

willis936 wrote: post #5

USB 4 AKA USB 4 Gen2x2 USB 4 (opt) AKA USB 4 Gen3x2 They had a chance to fix their colossal fuckup and they decided not to.

In marketing and on cables they've chosen to use the terms USB4 20Gbps and USB4 40Gbps, so at least that's explicit. There's also officials ways to mark cables as being 100W or 240W capable.
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