Is that year 2025...
USB Cheat Sheet
61–70 of 174 posts
Re: USB Cheat Sheet
#62Earlier quoted context omitted.
That’s a good point although optical usb3 and thunderbolt3 cables tend to be advertised with electrical isolation as a feature and suggest using an external hub to provide power.[1] [1] https://www.corning.com/optical-cables-by-corning/worldwide/...
Whoa, that pricing is quite a bit.
Yeah that must be the real reason it didn’t catch on as a default. Light peak did have cheaper cables though, the optical part was in the connector, not the cable. The connector was a usb-a connector if I remember correctly.. and the history is actually pretty interesting! Apparently that connector was deemed proprietary and frowned upon by the usb folks for causing consumer confusion[1]. Kind of hilarious now, seeing how thunderbolt 1/2 ended up barely being adopted outside of Apple and usb itself is a confusing mess these days.
[1] https://www.theverge.com/2011/10/14/2490694/how-sony-acciden...
Re: USB Cheat Sheet
#63Ah USB. In the old days it was different cables for different things, nowadays it's 1 connector for everything but beware, the cable might physically plug into the socket, but whether you'll get the functionality you want?
Just how many devices do you meet that regularly hit those edge cases? Outside 4K+ multimonitor connections?
(It's really popular and easy to bash on USB on this forum, but it turns out that in real life your USB-C device will "just work" for pretty much all setups outside really fringe high performance ones. And even those will usually just negotiate lower rate.)
Re: USB Cheat Sheet
#64Earlier quoted context omitted.
Whoa, that pricing is quite a bit.
Yeah that must be the real reason it didn’t catch on as a default. Light peak did have cheaper cables though, the optical part was in the connector, not the cable. The connector was a usb-a connector if I remember correctly.. and the history is actually pretty interesting! Apparently that connector was deemed proprietary and frowned upon by the usb folks for causing consumer confusion[1]. Kind of hilarious now, seein…
> Kind of hilarious now, seeing how thunderbolt 1/2 ended up barely being adopted outside of Apple
Which is to a large degree the fault of Intel restricting the TB spec to hell and back.
Re: USB Cheat Sheet
#65Some 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…
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% (because 8 data bits are encoded into 10 bits sent over the wire, which does not matter for the user).
All these misleading marketing data rates have been introduced by Intel, who did not follow the rules used in vendor-neutral standards, like Ethernet.
So PCIe 1 is 2 Gb/s, PCIe 2 & USB 3.0 are 4 Gb/s and SATA 3 is 4.8 Gb/s.
So USB "5 Gbps" => 500 MB/s (not 625 MB/s), and after accounting for protocols like "USB Attached SCSI Protocol", the maximum speed that one can see for an USB SSD on a "5 Gbps" port is between 400 MB/s and 450 MB/s.
The same applies for a USB Type C with 2 x 5 Gb/s links.
As other posters have already mentioned, USB 3.1 a.k.a. the "Gen 2" of later standards has introduced a more efficient encoding, so its speed is approximately 10 Gb/s.
The "10 Gbps" USB is not twice faster than the "5 Gbps" USB, it is 2.5 times faster, and this is important to know.
Re: USB Cheat Sheet
#66Like 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...
Re: USB Cheat Sheet
#67USB 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.
Their issue was not the naming for consumer or tech user, their issue was "how do we allow any random laptop from claiming latest usb despite not actually supporting it".
It was super obvious with usb 3 and its sub versions, and it gets even worse with 4.
Re: USB Cheat Sheet
#68Earlier quoted context omitted.
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…
Can be USB 3 [...] USB 2, so it is a bit hard to tell. ...or Thunderbolt, USB 4, DisplayPort (through Alt-mode or encapsulated in Thunderbolt), or HDMI (Alt-mode), or MHL (Alt-mode), USB Power Delivery... Unfortunately, not every cable with USB-C connectors can carry all of these. E.g. there are USB-C cables that can only carry USB 2. Or cables that can carry USB 3, but not Thunderbolt. Also, not all cables can carry…
There was a period of time where a google engineer was producting review on amazon about which usb-c cable would make your laptop burn. That was fun, and totally not the sign of an overbloated standard.
Re: USB Cheat Sheet
#69I have a related question: Is the official name USB 3.2 Gen 2x2 or USB 3.2 Gen 2×2 (x vs ×)?
Which USB do I choose for a 4x4 offroad adventure?
Re: USB Cheat Sheet
#70Earlier quoted context omitted.
Not my area of expertise, but maybe some (unrealistic) options include using fiber optics for the data lines, or adding more data lines.
There already exists some fiber-optic USB cables that come in lengths >50m and with support for USB 3.1 so it doesn't seem like a very unrealistic option.
Redmere chips also proved HDMI can go very, very far with a little extra investment. I've run 4K signals hundreds of feet with them. We've seen this problem solved several times, I can't imagine it's physically impossible with USB-C.