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I stopped trusting USB-C cable labels and started testing them

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Re: I stopped trusting USB-C cable labels and started testing them

#161
The problem isn't inherently USB, it's companies producing cables without properly defining specs.

If you want to be certain a USB cable works, buy it from a brand that sells certified (USB-IF) cables with a particular spec you want. For example, Club3D.

Yes, they'll cost more but you can be decently certain that you don't have to fiddle with it. I replaced all USB cables I own with certified ones. Since then, not a single issue with slow charging, display resolutions, frames, or data transfers.

Re: I stopped trusting USB-C cable labels and started testing them

#162
just don't buy cables from generic or awful brands, you can go with some reputable ones like cablematters,startech, caldigit, or satechi, also you can check USB-IF members. For other cables like displayport, just buy only certified cables that can be checked on displayport site, before buying any.

same for thunderbolt, etc.

you may pay a bit more, but they will comply the specs and be higher quality than the other generic brands.

Re: I stopped trusting USB-C cable labels and started testing them

#163
post #82

Earlier quoted context omitted.

> There shouldn't even need to be a label. A USB-C cable should be a USB-C cable should be a USB-C cable. Then USB is forever frozen in time, unless we start using new connectors. This was the tradeoff we got when standardizing on one connector. The protocol versions change (USB, USB-PD, Thunderbolt), the cables that go between each connector change based on the needs of the spec they supports. But the connectors sta…

> now we’re living in the hell we asked for N=1, but my quality of life has greatly improved. Literally all devices I use daily (laptop, phone, mp3 player, Bluetooth speaker, headphones) I charge from a single cable. I'm still grateful for this unification every time I charge my phone via the laptop charger.

Now we live in a world where any cable can connect any two devices, but what happens and what’s supported is a complete and total crapshoot. The more devices and cables you own, the more chaotic things become.

I have devices that take USB-C cables but won’t charge if the cable supports USB-PD.

I have a monitor that supports Thunderbolt 3 and two Thunderbolt 3 laptops. It took me multiple tries with various switches and Thunderbolt cables to find a combination that worked.

I have had multiple other situations like this, and the only practical solution I’ve found is to aggressively get rid of cables of questionable provenance, unless you can keep them permanently connected to or associated with the device they came with.

I suspect I’m running into this sooner than most because I’ve gone all-in on USB-C. I have gotten rid of every device possible that used USB micro or USB-A.

For simple electronics that just need to charge? Fine, sure, outside of random cable/device pairs charging slower than expected, it’s nice. For anything that actually depends on features on the cable or on a combination of features supported by the devices on each end? Total chaos.

Re: I stopped trusting USB-C cable labels and started testing them

#164

The Treedix cable tester is awesome. Ordered one after reading Terence Eden's positive review* and went through all my cables the day it arrived. My favorite was the cable with only the ground connected; went immediately into the bin. *) https://shkspr.mobi/blog/2025/06/gadget-review-treedix-usb-c...

It definitely looks to be one of the better ones. Since many of these products use same generic Chinese platforms, I looked for a similar product on Aliexpress since they have better shipping for me, but didn't find a full analog. Had to use a forwarder to order from Treedix—only to have it shipped in a very roundabout way from China.

Re: I stopped trusting USB-C cable labels and started testing them

#165
I coded this as an exercise https://apps.apple.com/app/cable-detective/id6765963737?mt=1... - reads everything it can about the plugged in cables and devices, feeds it to Apples internal AI.

In the latest version it even doesn't crash the computer anymore after rapid plug/unplugging action.

Re: I stopped trusting USB-C cable labels and started testing them

#166

> But I shouldn't have had to do any of this. It's time cables came with a label of their own, or some sort of color coding. There shouldn't even need to be a label. A USB-C cable should be a USB-C cable should be a USB-C cable. There should be a single connectivity/performance spec, and if the cable meets it, it can be called a USB-C cable, and if it doesn't, it should have to be marketed as USB-JUNK or something. T…

This is basically Thunderbolt and why most of cables I buy are either braided charge cables or Thunderbolt 3/4 for data. They’re usually labelled with their version too.

You do have to worry about active bs passive after 1m or so length.

I am not a fan of the USB-C spec, the naming of all the sub specifications/versions is a nightmare.

Re: I stopped trusting USB-C cable labels and started testing them

#167

Earlier quoted context omitted.

Think about it. You need to generate a precise, calibrated, 40GHz signal, transmit it, then precisely measure the returned signal for phase, amplitude, and waveform integrity -at that speed. Oscilloscopes and logic analyzers that run at that speed, are damn expensive.

Someone could do an equivalent-time sampling instrument for not much money, if the market were there. It's probably not, though.

Time sampling isn’t enough.

You need to at least look at waveform integrity (which can be approximated, by doing things like looking for harmonics).

For example, you may send in a 40 GHz square wave, and get back a wave full of ringing, or a sine or sawtooth wave. It’s damn difficult to maintain clean square waves, at that frequency. The cable could also double as a microwave antenna.

Since it’s digital information, some waveform alterations are OK, but not too much. You need fairly clear state transitions. Ringing, or waveform distortion, can introduce extra (or fewer) transitions; thus, completely changing the data.

Re: I stopped trusting USB-C cable labels and started testing them

#168
post #56

Earlier quoted context omitted.

This keeps needing to be pointed out every thread this appears on. Plenty of cables have eMarkers that claim "40Gbps" or whatever speeds, or support 240W PD...but absolutely cannot deliver either of those. And none of these consumer level testers can test either of those claims. Resistance measurements can cursorily test claims of 240W but resistance changes with temperature which changes with current...so unless you…

Yeah — "the eMarker said 40Gbps" is basically the same problem as trusting the print on the jacket. For home use I've ended up treating real capability as an empirical property of the specific cable+port+device combo: does this exact cable drive this monitor at the mode I want, under load, for an hour? If yes, it gets a colored heat-shrink band and never leaves that use case. Everything else is a phone/charge cable u…

That’s a very practical approach.

Re: I stopped trusting USB-C cable labels and started testing them

#169
post #72

> But I shouldn't have had to do any of this. It's time cables came with a label of their own, or some sort of color coding. There shouldn't even need to be a label. A USB-C cable should be a USB-C cable should be a USB-C cable. There should be a single connectivity/performance spec, and if the cable meets it, it can be called a USB-C cable, and if it doesn't, it should have to be marketed as USB-JUNK or something. T…

Unless you want all cables to be thick, $60, and cap out at 1 meter long, this is not a reasonable standard. 480mbps USB-C is perfectly adequate for many applications. Likewise for 60W cables.

Actually, different cables should be called something different.
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