USB-C has been with us for over a decade now, and we have ten years worth of confusion to show for it. Two cables might appear identical, yet one will push 40 gigabits per second and 240 watts while another barely manages USB 2.0 speeds and 15 watts. Often there’s no marking, no clue, and no real way to know what a cable can handle until it fails at an inconvenient moment.
That’s what pushed me to pick up two cable testers from Amazon, one inexpensive and one considerably more advanced to get to the bottom of what’s tangled up in my rats nest of USB-C cables.
Check it out in my latest video.
The simpler of the two, from a company called Treedix (compensated affiliate link) lights up its board with pin-by-pin results. It works, but it asks you to know USB-C well enough to interpret what each light means. The more expensive unit, called the CaberQu (compensated affiliate link), offers a cleaner readout with data rates, supported modes, power levels, and even cable health. It also identifies the manufacturer and can sync its results to a mobile app. That turned out to be surprisingly useful for labeling cables and keeping track of what each one can actually do.
Running different cables through both testers made the differences obvious. A cable that was labeled at 40 Gbps and 240 watts really did meet those specs. Another cable that looked nearly the same topped out at USB 2.0 speeds and only 15 watts. One of my mystery cables supported 100-watt charging but only USB 2.0 data. These testers don’t stress-test power delivery, but they do verify what the cable is built to handle.
The testers didn’t always agree on Thunderbolt 3 cables, though—the CaberQu consistently read them at 20 Gbps when they should be twice that. My Mac reports 40 Gbps when I use them, so I’m chalking that up to a firmware quirk.
USB-C isn’t the only thing these tools can handle. The Treedix tester accepts USB-A and USB-B connectors too, and it confirmed the performance markings on several older cables. I even fed photos of the indicator lights to an AI model, which interpreted the pinouts pretty accurately—useful for anyone who doesn’t want to memorize USB diagrams. CaberQu’s makers tell me that USB adapters can be used on their product for older cables.
USB cables aren’t required to go through a certification process the way Thunderbolt cables are. A Thunderbolt cable must be certified to carry the logo. USB cables do not, though USB-IF is beginning to roll out an optional certification process. That means plenty of cables on the market claim capabilities without a third party ever confirming them.
After working through my collection, I’m glad to see tools like these that can remove a lot of uncertainty around USB-C. But the fact that we need tools like this underscores just how consumer-unfriendly the USB standard has become.