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A nearly perfect USB cable tester

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Re: A nearly perfect USB cable tester

#31

Post by atoav »

HPsquared wrote: post #17
jmalicki wrote: post #14

Earlier quoted context omitted.

So you're saying there is something to audiophile grade HDMI cables?

With digital signals and ECC, the cable need only be "good enough" to get perfect data transfer through the system.

Correct. But especially if you're using long cables a cable with more "headroom" in the eye diagram will perform more reliable than one that is just at the edge of breakup.

For home use that doesn't matter usually, but I for example run events where I need the cable to work also after 10 people stepped on it and then this can become a significant thing.

Not in terms of quality, but reliability.

Re: A nearly perfect USB cable tester

#32

Post by ChrisMarshallNY »

TeMPOraL wrote: post #26
graemep wrote: post #13

Earlier quoted context omitted.

I suspect most users do not even realise things are slow.

Oh, they very much do. But like with everything in technology, they can do fuck all about it, so they resign and maybe complain to you occasionally if you're the designated (in)voluntary tech support person for your family and friends. Regular people hate technology, both for how magical and how badly broken it is, but they've long learned they're powerless to change it - nobody listens to their complaints, and the w…

They also tend to hate technology, because us nerds are often unbearable.

They hate having to go through people that get them upset, in order to use their kit.

Not just tech (although it’s more prevalent). People who are “handy” can also be that way (but, for some reason, techies tend to be more abrasive).

I’ve learned the utility of being patient, and not showing the exasperation that is often boiling inside of me.

Re: A nearly perfect USB cable tester

#33

Post by MaxikCZ »

seanalltogether wrote: post #20

I wasn't surprised to learn that when Linus Tech Tips released those new usb-c cables, that they all sold out almost instantly. They put their entire reputation on the line to claim (and label) the exact capabilities of their usb cables. Isn't that all we really want?

[flagged]

Re: A nearly perfect USB cable tester

#34

Post by imglorp »

avian wrote: post #6
Gigachad wrote: post #3

The thing that has been bothering me for a while is that the USB spec allows for software detection of capabilities. You can read the emarker data and see the supported protocols, speeds, voltages, etc. But there is not standard for usb controllers to present this data to the OS. So it’s stuck in the low level firmware and never passed up. In theory we could have a popup box that tells you that both your computer and…

> In theory we could have a popup box that tells you that both your computer and other device support higher speeds/more power, but your cable is limiting it. I'm pretty sure my old Dell XPS laptop with Windows 10 had pop-ups just like this. "This device can run faster" or something.

I wonder if it's possible for a regular machine with two high speed ports to do a cable test by itself. Maybe it can't test all the attributes but could it at least verify speed claims in software?

Re: A nearly perfect USB cable tester

#36

Post by jmalicki »

atoav wrote: post #30
jmalicki wrote: post #25

Earlier quoted context omitted.

I just need to make a cable with better eye diagrams so I can market it to AV enthusiasts with "golden eyes"!

Well the thing is better doesn't mean better quality here. Better means you can use a longer cable or abuse the cable for longer till it dies. This is a big part of what makes any pro gear expensive: reliability. If you just connect your home hifi to your speakers in an acoustically untreated space, you could also just use a bunch of steel wire coathangers and get an indistinguishable result. Even a el-cheapo store b…

I have seen shielding and gauge make quite a difference for cables carrying analog signals!

Re: A nearly perfect USB cable tester

#37

Post by vladvasiliu »

Gigachad wrote: post #3

The thing that has been bothering me for a while is that the USB spec allows for software detection of capabilities. You can read the emarker data and see the supported protocols, speeds, voltages, etc. But there is not standard for usb controllers to present this data to the OS. So it’s stuck in the low level firmware and never passed up. In theory we could have a popup box that tells you that both your computer and…

> But there is not standard for usb controllers to present this data to the OS. So it’s stuck in the low level firmware and never passed up. In theory we could have a popup box that tells you that both your computer and other device support higher speeds/more power, but your cable is limiting it.

There is. I used to use a KVM with USB 2 ports connected to my PC's USB 3 port, to which I connected a monitor with integrated USB 3 hub to drive my keyboard and mouse. Windows would show a popup every time telling me that I should use a faster cable.

There are also popups telling me that my laptop is connected to a "slow" usb-c charger.

Re: A nearly perfect USB cable tester

#39

Post by tom_alexander »

jmalicki wrote: post #24
HPsquared wrote: post #17

Earlier quoted context omitted.

With digital signals and ECC, the cable need only be "good enough" to get perfect data transfer through the system.

His link made very clear the issues of jitter and flickering.

These two statements aren't mutually exclusive. The link is looking at the analog signal through an oscilloscope. The person you replied to is pointing out that after decoding and applying error correction, you can still end up with the same digital signal output. So the eye diagram charts are useful for detecting the quality of the cable, but as long as the quality is past a certain threshold, it does not matter.
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