The only wrinkles for me are that Macs apparently don't interrogate cables when they don't have to, i.e., when the power adapter supplies <= 60W (not sure if that's a USB-C protocol or an Apple implementation limitation) and that the website copy is full of GPT-isms, which makes me suspect that some of the output might be assumed instead of empirically validated as well.
> I'm using the hardware tester from $INSERT_NAME_HERE
Oh god not again... before everyone starts naming their favourite brand, here's a 265 comment HN thread[1] (from last week !) on why these cheap USB-cable "testers" are not worth anything.
TL;DR You need a six-figure wallet to seriously call anything a "hardware tester" for USB cables. User ChrisMarshallNY has a one-liner summary buried in that thread:
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.
Yep, I probably have the same one. Insanely useful, and it is also crazy how much variance there is in cables. You can’t believe what the sellers claim, so many times they end up being less capable than claimed.
Would this tell me if a cable is close to the end of it's life? I like to travel light and I've had cables (mostly phone/pad power) go out on trips after working as expected when I packed.
I think you would need something that tracks relevant per cable metrics over time to see if it is degrading.
That one just says yes/no, but maybe yes/no starts to flicker around its end of life?
Nod - that's what I was thinking. I expect it's often the connectors that deteriorate so perhaps moving them around while plugged in would tell me. Seems like a useful tool to have around.
I'm curious if this also works for USB-A to USB-C. The use case: My Suburu has USB-A inputs and only allows wired Carplay. When I upgraded my iPhone and ditched Lightning, I had to try 6 different cables from my cable drawer to find one that supported data transfer.
I have so many cables I've accumulated over the years, I should either purge or at least categorize the functionality of each.
I literally spent more than an hour yesterday debugging issues with USB-C cables that I wasn't aware were charging only, and this shows up today... Better late than never, I suppose, and definitely worth my ten quid.
I was trying to figure out slow network speeds one day and I finally swapped an ethernet cable and got full speed.
It turns out some ethernet cables are missing wires - and capped at 100Mbps! Wait what? I didn't even know that was a thing. I don't know where I got the wire, but into the trash it goes.
If you can afford it, I'd honestly throw these out. "Charging only" is not a spec-compliant thing in USB-C, and personally I wouldn't want to re-discover which devices do and don't support them every time I just want to quickly grab a cable.
What's less easy to replace are all these damn USB-C devices lacking the UFP-identifying circuitry that only work on USB-A chargers using A-to-C cables...
To be clear, they're not literally "charging only", AIUI they're spec-compliant cables with USB2.0 480Mbps and power delivery, and they're allowed to not have the four SuperSpeed wire pairs. They're still useful for low bandwidth devices (like charging my keyboard/mouse).
Incidentally — I spent an inordinate amount of time searching for USB3.2 cables on Amazon, and the vast majority of cables were actually just USB2.0 cables with PD support, and not actual Full-Featured cables.
Ah, I love these as they're generally much thinner/lighter/more flexible than USB-C 3 cables but still support at least 60W power delivery! Advertising them as USB 3 is a shame, though.
I would recommend getting one of the small cable testers, like the one from Treedix. Gives you all sorts of information very quickly, including resistance levels and capabilities.
I came here to ask the same thing. I did find a Linux tool with the same name and purpose but that seems to be an entirely different codebase: https://github.com/nedrichards/whatcable-linux
I have a handful of wireless keyboards that just absolutely refuse to negotiate for charging with certain cables at all, so I'm hoping this will help me at least figure out what those keyboards are looking for in terms of cable.
Something that keeps needing to be pointed out every thread this stuff appears on: What these tools report are not functionally different from just believing "what's on the packaging", despite the misleading marketing claims.
These tools read a chip called an "eMarker". These eMarkers are programmed to say whatever the manufacturer wants them to say - there's no requirement that the information be based in reality. 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 software or hardware testers can actually test either of those claims. They can only take the cable's own claims at face value.
Resistance measurements can cursorily test claims of 240W but resistance changes with temperature which changes with current...so unless your tester puts 5 amps down the wire for 5 minutes and then tests resistance it's not a very good test. AFAIK none of the testers flow 5 amps through the cable.
Actual maximum data throughput is very hard to know. The only way to really "know" how much data can flow through a cable is with an expensive oscilloscope or cable tester. Because 80Gbps cables run at ~13GHz, at minimum you need a 26GHz scope (Nyquist–Shannon sampling theorem) or more practically a 52GHz scope. And it turns out it's really expensive to measure electrical signals 52 billion times per second. The necessary devices start at $15,000 (cable signal integrity tester) [0] on the very low end and only work for max 10Gbps USB 3.2 cables, or past $270,000 for 80Gbps USB4 cables (proper 60GHz oscilloscope) [1].
On the high end, each signal integrity test device can actually cost $1-2 million [2] where the base unit starts at $670,000 plus then spending additional money for hardware-accelerated analysis, specialized active probes, and the specific PAM-3 / USB4 compliance software packages.
Great utility.
The only wrinkles for me are that Macs apparently don't interrogate cables when they don't have to, i.e., when the power adapter supplies <= 60W (not sure if that's a USB-C protocol or an Apple implementation limitation) and that the website copy is full of GPT-isms, which makes me suspect that some of the output might be assumed instead of empirically validated as well.
I'm using the hardware tester from Treedix in which you have to plug both ends of the cable and which tests a lot of things, I'm quite fond of it.
I have a basket with a lot of USB-c cables and without the tester I can't remember (nor guess) which one does what.
> I'm using the hardware tester from $INSERT_NAME_HERE
Oh god not again... before everyone starts naming their favourite brand, here's a 265 comment HN thread[1] (from last week !) on why these cheap USB-cable "testers" are not worth anything.
TL;DR You need a six-figure wallet to seriously call anything a "hardware tester" for USB cables. User ChrisMarshallNY has a one-liner summary buried in that thread:
[1] https://news.ycombinator.com/item?id=49152255Yep, I probably have the same one. Insanely useful, and it is also crazy how much variance there is in cables. You can’t believe what the sellers claim, so many times they end up being less capable than claimed.
Would this tell me if a cable is close to the end of it's life? I like to travel light and I've had cables (mostly phone/pad power) go out on trips after working as expected when I packed.
I think you would need something that tracks relevant per cable metrics over time to see if it is degrading. That one just says yes/no, but maybe yes/no starts to flicker around its end of life?
Nod - that's what I was thinking. I expect it's often the connectors that deteriorate so perhaps moving them around while plugged in would tell me. Seems like a useful tool to have around.
Nice. You just got them a sale from me. I have a crap ton of cables so this will come in handy.
I'm curious if this also works for USB-A to USB-C. The use case: My Suburu has USB-A inputs and only allows wired Carplay. When I upgraded my iPhone and ditched Lightning, I had to try 6 different cables from my cable drawer to find one that supported data transfer.
I have so many cables I've accumulated over the years, I should either purge or at least categorize the functionality of each.
I see other folks provided options, in case you want to avoid aliexpress, this one worked for me for the past 4 years
https://a.co/d/0d9EOGRW
Does require a bit of setup, can scan reviews to see if people have optimized a config for your specific vehicle
I'd recommend a wireless CarPlay adapter. I bought one for my car, and it's a game-changer.
This adapter works with my Android phone and makes my Android Auto wireless: https://aliexpress.com/item/1005008214786824.html
But it is the second product I tried; the first one didn't work (it's a 2020 Stellantis car). So, YMMV.
I literally spent more than an hour yesterday debugging issues with USB-C cables that I wasn't aware were charging only, and this shows up today... Better late than never, I suppose, and definitely worth my ten quid.
I was trying to figure out slow network speeds one day and I finally swapped an ethernet cable and got full speed.
It turns out some ethernet cables are missing wires - and capped at 100Mbps! Wait what? I didn't even know that was a thing. I don't know where I got the wire, but into the trash it goes.
If you can afford it, I'd honestly throw these out. "Charging only" is not a spec-compliant thing in USB-C, and personally I wouldn't want to re-discover which devices do and don't support them every time I just want to quickly grab a cable.
What's less easy to replace are all these damn USB-C devices lacking the UFP-identifying circuitry that only work on USB-A chargers using A-to-C cables...
To be clear, they're not literally "charging only", AIUI they're spec-compliant cables with USB2.0 480Mbps and power delivery, and they're allowed to not have the four SuperSpeed wire pairs. They're still useful for low bandwidth devices (like charging my keyboard/mouse).
Incidentally — I spent an inordinate amount of time searching for USB3.2 cables on Amazon, and the vast majority of cables were actually just USB2.0 cables with PD support, and not actual Full-Featured cables.
Ah, I love these as they're generally much thinner/lighter/more flexible than USB-C 3 cables but still support at least 60W power delivery! Advertising them as USB 3 is a shame, though.
I would recommend getting one of the small cable testers, like the one from Treedix. Gives you all sorts of information very quickly, including resistance levels and capabilities.
Is there something like this for Windows/Linux?
ChromeOS firmware has a bunch of this built in - it's super cool. https://nelsonslog.wordpress.com/2026/01/05/chromebooks-iden... and https://www.reddit.com/r/UsbCHardware/comments/1pyojjd/comme... and https://chromium.googlesource.com/chromiumos/platform2/+/HEA... is where I found out about it. A lot of the clever capabilities rely on the firmware that you have. Source - having spent a while a few weeks back getting Codex to poke at this topic on my machine https://github.com/nedrichards/whatcable-linux/blob/main/doc... since framework do reuse parts of the ChromeOS Embedded Controller in their firmware.
"This is a Linux-native reimplementation inspired by darrylmorley/whatcable"
https://github.com/nedrichards/whatcable-linux
But (hazard guess) it comes with a headless CLI binary (no GUI libraries needed) so probably could be ported to Linux (easily with an LLM?)
https://github.com/darrylmorley/whatcable
There are options on Linux that you can google up (I don't know enough about any of them to endorse them by linking to one in particular).
As I understand it, Windows doesn't expose the necessary low-level hardware information for something like this to be possible.
A quick search found https://github.com/nedrichards/whatcable-linux, haven't tried it myself though
I came here to ask the same thing. I did find a Linux tool with the same name and purpose but that seems to be an entirely different codebase: https://github.com/nedrichards/whatcable-linux
I have a handful of wireless keyboards that just absolutely refuse to negotiate for charging with certain cables at all, so I'm hoping this will help me at least figure out what those keyboards are looking for in terms of cable.
Something that keeps needing to be pointed out every thread this stuff appears on: What these tools report are not functionally different from just believing "what's on the packaging", despite the misleading marketing claims.
These tools read a chip called an "eMarker". These eMarkers are programmed to say whatever the manufacturer wants them to say - there's no requirement that the information be based in reality. 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 software or hardware testers can actually test either of those claims. They can only take the cable's own claims at face value.
Resistance measurements can cursorily test claims of 240W but resistance changes with temperature which changes with current...so unless your tester puts 5 amps down the wire for 5 minutes and then tests resistance it's not a very good test. AFAIK none of the testers flow 5 amps through the cable.
Actual maximum data throughput is very hard to know. The only way to really "know" how much data can flow through a cable is with an expensive oscilloscope or cable tester. Because 80Gbps cables run at ~13GHz, at minimum you need a 26GHz scope (Nyquist–Shannon sampling theorem) or more practically a 52GHz scope. And it turns out it's really expensive to measure electrical signals 52 billion times per second. The necessary devices start at $15,000 (cable signal integrity tester) [0] on the very low end and only work for max 10Gbps USB 3.2 cables, or past $270,000 for 80Gbps USB4 cables (proper 60GHz oscilloscope) [1].
On the high end, each signal integrity test device can actually cost $1-2 million [2] where the base unit starts at $670,000 plus then spending additional money for hardware-accelerated analysis, specialized active probes, and the specific PAM-3 / USB4 compliance software packages.
0: https://www.totalphase.com/products/advanced-cable-tester-v2...
1: https://www.edn.com/12-bit-oscilloscope-operates-up-to-65-gh...
2: https://www.eevblog.com/forum/testgear/uxr1104a-infiniium-ux...
Small question: did anybody succeed to pay via Apple Pay?