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 other device support higher speeds/more power, but your cable is limiting it.
Apple seems best able to do this since they control the hardware and OS, yet they aren’t doing it either. Users are just left to be confused about why things are slow.
> 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.
> that's just when plugging in a USB 3 device into a USB 2 port
Dell XPS laptops (and some others) can also warn if the charger isn't providing the full wattage the laptop is rated for. This warning is an option that can be turned off in the BIOS settings.
I usually turn it off because I sometimes intentionally do day trips with a smaller/lighter portable charger which delivers 45w to my laptop which can need up to 65w due to having a discrete GPU. However, 45w is more than sufficient to charge the laptop during normal use on the Balanced power plan with iGPU. I only need more than 45w when gaming with the discrete GPU active.
Just this morning, my old Latitude failed to boot with a “this charger is only giving 20W and that’s not enough to boot this laptop” error. (I was testing a new USB-C charger that’s obviously going back.)
Weirdest part was it was 100% charged, so could have booted with 0 Watts of charger but decided not to boot with 20 Watts more.
My wife's work laptop gives this stupid warning anytime any USBC charger is plugged in, other than the Dell brick. So even a dock delivering 100w would get a complaint. The Dell brick offers non-standard charging at 140w, which can't get replaced by standards compliant, smaller chargers.
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?
Perhaps someday it will earn the same level of importance as charging; iOS 26 calls out slow chargers on their iPhones, so you can run to the Apple Store and buy a fast one!
They probably have to weigh potential new hardware sales against added complexity. I have counterpoints too but: I believe they try to protect users’ mental models of their ecosystem (which perhaps I appreciate when I don’t notice, and can’t stand when something is uncustomizable). Like there are enough variables they don’t trust us with as it is.
> 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.
It's fun to see the Treedix tester come up on HN. I got one a few months back and have quite enjoyed using it. One thing which I did find interesting was that one of the cables had the emarker data lie. IIRC, the emarker data would suggested it supported much higher speeds and wattage than it did. Fortunately, the other testing screens successfully detected it only had USB 2.0 wires even though it claimed to support 40 GB/s.
Does it matter, for anyone other than hardcore geeks? All the OS would care about is how much power can it deliver and what data speed it provides, not whether the exception handling on page 4,096, section 4(a)2.1, paragraph 4 of the spec, has been implemented.
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?
I actually purchased one of these as this article has surfaced before.
It’s well worth the hype, I used it to audit all my cables (both for home and work) and it’s amazing how many thick and unwieldy cables are actually terrible for data.
For example I purchased a pair of B&W Px8 S2 noise cancelling headphones, which boast a DAC if you connect via USB-C directly, the cable it came with though was thick but only rated for USB 2.0 speeds. These headphones cost more than AirPods Max, which are themselves considered overpriced, and include comforts like nappa leather; so shipping with a chunky cable that doesn’t even carry decent data feels like a bizarre oversight. Apple’s own USB-C cables manage the same power delivery at less than half the thickness with a woven shell. You’d assume a premium product would at least match that.
Honourable mention to the USB-C cables that ship with Dell Ultrasharp monitors (both pre-USB4 and post). Those support basically everything except Thunderbolt 4 despite being unmarked.
One thing to realize is that especially for high resolution video cables these cheap testers can't really deliver. The way to test them is a eye diagram (see: https://incompliancemag.com/eye-diagram-part2/ ) and testers with that capsbility cost upwards of 10.000 Eurodollars.
What I'm looking for is a differential signal tester, where you can breakout any arbitrary cable or traces and test the properties of the wire with different frequencies. It should be able to measure interesting properties such as resistance, capacitance, inductance, phase/length difference, wire length, etc.
One of these devices for approximately $100 would sell all day long.
Like the price point and portability of the base Treedix testers.
Talking about near perfect wishlist:
Some standard hardware with fail-safe power connections
a set of fully wired ports like in display-less Treedix USB platine tester version.
On the other side powered and extended diagnostics through USB-C can then be done from any smartphone or pc providing the display and updateable extended software layer.
Bonus for connectivity to some brother label printers.
Similarly: Is there a USB-C power delivery adapter to force directionality? I needed to siphon off power from small batteries into a larger pack (that could supply more power out than the small packs) in a power outage. I absolutely could not force my larger power station to accept a charge and it kept pushing power back the wrong direction despite which ends of the cable I plugged in first.
> The only downside of the USB cable tester is that I would love to support more plugs on the B side: USB-A (for my Frankencables) and USB B (which everyone but seems to think extinct).
Music production peripherals, until the recent USB C transition, commonly used USB B for some reason. Anyone know why?
As someone who really doesn't care about learning the details, and just want one USB-C cable that does it ALL to put in my backpack what should I buy ?
Brilliant little device. I will be picking one up ASAP!. Didn't know that lying cables were a thing but I have a ton of charge only cables?!
I speculate USB B wasn't included because there are only really two types, 2.0 (regular size) and 3.0 (has an obvious extension on the connector). There also don't tend to be power-only A-B cables because they are usually found on printers, Arduino s, ... And not for charging devices.
Fun fact: A Xiaomi fast charge cable (with orange plugs) has an extra contact on the A end to support USB C PD out of a USB A charger.
173 comments
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.
Apple seems best able to do this since they control the hardware and OS, yet they aren’t doing it either. Users are just left to be confused about why things are slow.
> 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.
> that's just when plugging in a USB 3 device into a USB 2 port
Dell XPS laptops (and some others) can also warn if the charger isn't providing the full wattage the laptop is rated for. This warning is an option that can be turned off in the BIOS settings.
I usually turn it off because I sometimes intentionally do day trips with a smaller/lighter portable charger which delivers 45w to my laptop which can need up to 65w due to having a discrete GPU. However, 45w is more than sufficient to charge the laptop during normal use on the Balanced power plan with iGPU. I only need more than 45w when gaming with the discrete GPU active.
Weirdest part was it was 100% charged, so could have booted with 0 Watts of charger but decided not to boot with 20 Watts more.
They probably have to weigh potential new hardware sales against added complexity. I have counterpoints too but: I believe they try to protect users’ mental models of their ecosystem (which perhaps I appreciate when I don’t notice, and can’t stand when something is uncustomizable). Like there are enough variables they don’t trust us with as it is.
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.
Using DevCheck might show 2.2A/9V as an example.
I don’t know if they check that via USB protocol, or if they are measuring the actual power draw on the USB port.
In order to use the device, I had to connect it via an externally powered USB hub.
It’s well worth the hype, I used it to audit all my cables (both for home and work) and it’s amazing how many thick and unwieldy cables are actually terrible for data.
For example I purchased a pair of B&W Px8 S2 noise cancelling headphones, which boast a DAC if you connect via USB-C directly, the cable it came with though was thick but only rated for USB 2.0 speeds. These headphones cost more than AirPods Max, which are themselves considered overpriced, and include comforts like nappa leather; so shipping with a chunky cable that doesn’t even carry decent data feels like a bizarre oversight. Apple’s own USB-C cables manage the same power delivery at less than half the thickness with a woven shell. You’d assume a premium product would at least match that.
Honourable mention to the USB-C cables that ship with Dell Ultrasharp monitors (both pre-USB4 and post). Those support basically everything except Thunderbolt 4 despite being unmarked.
It seems to be a more comprehensive "Make sure the lines go where they are supposed to" tester. Looks pretty good.
But the devices that test things like transmission speed, are a lot more expensive.
I think that many of the issues that this device tests, can be mitigated by simply buying cables from reputable sources.
One of these devices for approximately $100 would sell all day long.
Talking about near perfect wishlist:
Some standard hardware with fail-safe power connections a set of fully wired ports like in display-less Treedix USB platine tester version.
On the other side powered and extended diagnostics through USB-C can then be done from any smartphone or pc providing the display and updateable extended software layer.
Bonus for connectivity to some brother label printers.
They can still provide some power, but between a MacBook and official Apple power supply, they’ll keep flicking between charging and not charging.
I didn't know there were cable testers like this, thank you.
> The only downside of the USB cable tester is that I would love to support more plugs on the B side: USB-A (for my Frankencables) and USB B (which everyone but seems to think extinct).
Music production peripherals, until the recent USB C transition, commonly used USB B for some reason. Anyone know why?
> Access Denied
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Are they geoblocking the USA from even viewing their site for some reason?
I speculate USB B wasn't included because there are only really two types, 2.0 (regular size) and 3.0 (has an obvious extension on the connector). There also don't tend to be power-only A-B cables because they are usually found on printers, Arduino s, ... And not for charging devices.
Fun fact: A Xiaomi fast charge cable (with orange plugs) has an extra contact on the A end to support USB C PD out of a USB A charger.