USB Cheat Sheet • Hacker News Board

Re: USB Cheat Sheet

#71

Post by cosmotic » Thu, May 05, 2022, 2:47 PM UTC

Where's the standard speed?

Re: USB Cheat Sheet

#72

Post by notorandit » Thu, May 05, 2022, 2:49 PM UTC

kashunstva wrote: post #3

> May 05, 2025 The article is dated May 5, 2025. I've long been wondering about the future of USB.

Not to be read before: see article time stamp

Re: USB Cheat Sheet

#73

Post by notorandit » Thu, May 05, 2022, 2:51 PM UTC

stavros wrote: post #49

What does the U in USB stand for again?

Uikipedia

Re: USB Cheat Sheet

#74

Post by IvanK_net » Thu, May 05, 2022, 2:56 PM UTC

Fun fact: USB 2.0 webcams have been existing for over 10 years. USB 2.0 is 60 MB/s.

A pixel of an image is 3 Bytes. A 1920x1080 FullHD image is 6.2 MB. At 30 frames per second, second of a FullHD video is 186 MB. How did they do that?

Answer: frames are transferred as JPEG files. Even a cheap $15 webcam is a tiny computer (with a CPU, RAM, etc), which runs a JPEG encoder program.

Re: USB Cheat Sheet

#75

Post by moffkalast » Thu, May 05, 2022, 3:09 PM UTC

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.

Keep the same speeds, add more wires.

Re: USB Cheat Sheet

#76

Post by moffkalast » Thu, May 05, 2022, 3:13 PM UTC

All it's missing is the pinouts and the charger resistor divider setup definitions.

Re: USB Cheat Sheet

#77

Post by jbverschoor » Thu, May 05, 2022, 3:15 PM UTC

adrian_b wrote: post #65

belter wrote: post #38

Earlier quoted context omitted.

Also should be: 12 Mbps -> 1.43 MiB/s -> 1.5 MB/s 480 Mbps -> 57 MiB/s -> 60 MB/s 5000 Mbps (5 Gbps) -> 596 MiB/s -> 625 MB/s 10000 Mbps (10 Gbps) -> 1192 MiB/s -> 1250 MB/s 20000 Mbps (20 Gbps) -> 2384 MiB/s -> 2500 MB/s 40000 Mbps (40 Gbps) -> 4768 MiB/s -> 5000 MB/s

No, some of your rates are wrong. The so-called 5 Gb/s USB has a data rate of 4 Gb/s. The marketing data rates for Ethernet are true, i.e. 1 Gb/s Ethernet has a 1 Gb/s data rate, but a 1.25 Gb/s encoded bit rate over the cable. The marketing data rates for the first 2 generations of PCIe, for all 3 generations of SATA, and for USB 3.0 a.k.a. "Gen 1" of later standards, are false, being advertised as larger with 25% (…

Is that the same intel that “forgot” to mention that they overclocked a demo cpu and used ndustrial water chiller?

Re: USB Cheat Sheet

#78

Post by jbverschoor » Thu, May 05, 2022, 3:18 PM UTC

stavros wrote: post #49

What does the U in USB stand for again?

U-turn

Re: USB Cheat Sheet

#79

Post by navaati » Thu, May 05, 2022, 3:19 PM UTC

ProZsolt wrote: post #66

synergy20 wrote: post #59

Like the simple site design with a one page info about USB. someone please make similar one-page with tables about PCI Express, Ethernet, HDMI...

I created a cheat sheet for Ethernet, when I built my home network: https://github.com/ProZsolt/runbook/blob/master/ethernet-cab...

Really nice !

Today I learn that there is a 25 and 40G-BASE-T on copper, these PHY must heat like hell haha.

Re: USB Cheat Sheet

#80

Post by jbverschoor » Thu, May 05, 2022, 3:22 PM UTC

stavros wrote: post #49

What does the U in USB stand for again?

Actually, I think it’s just a upside down “∩”. Makes sense because the non-C connectors are always upside down, and all it does is intersect wires.