What is the C2C caberQU?

The C2C caberQU board applies a voltage to all pins of a cable and measures which ones are connected to the other end. It features LEDs for each of the 24 pins and even shield. So in total 25 LEDs offer all possible combinations for USB-C receptacle pin usage in different modes:

  • USB 2.0/1.1
  • USB Power Delivery
  • USB 3.0/3.1/3.2
  • Alternate Mode
  • Debug Accessory Mode
  • Audio Adapter Accessory Mode

Why did you make it?

The amount of possible USB C cable combinations is endless. If you use the wrong cable, data transmission may be slower than possible or certain devices may not work at all. In the USB C standard, the cable plays an important role and has to advertise itself as such. All of them need to have certain pins connected, some need to be grounded, some need to have resistors attached.

What makes it special?

Unfortunately there is no easy way to extract whether a certain cable can support a certain use case. If a cable has a broken pin, that makes it even worse, due to their unpredictable behaviour. The C2C caberQU cable tester solves this once and for all. By flipping the USB connectors, the opposing LEDs for some pins light up due to them not being mirrored. That's on purpose and defined in the USB C standard. The product is sold with one CR2032, the PCB and some basic instructions. The USB C cable is not included. You have to extract the needed pins for your desired usage on your own, unfortunately that can not be done universally for all possible combinations.


Insert both ends of a USB C to USB C cable into the C2C caberQU. This will make each LED which has any of the pins of connector II connected to connector I light up. Pins which have a resistor attached in the cable internally will make the corresponding LED light up less intense. The cable tester can not detect short circuits in between different pins, special function cables including diodes or any cables with active electronics.
The C2C caberQU does not consume any power while no cable is connected.


Useful LED combinations

The LEDs for the corresponding pins need to light up to make sure the desired mode is available. Please note that
shorted pins, diodes, active electronics or other faults/things inside the cable can provide false results. Options A
and B are for the two possible connector I orientations and can be inverted by flipping the cable at connector I.
If D+ and D- are connected, they only light up on one side of the tester. This is for compatibility with older USB
connector generations and can be inverted by flipping connector I.


The project is freely available on github, feel free to fork, download, improve and let me know ;)

About us


With a passionate interest about electronics and a keen motivation to bring well thought out products to you, we're always looking for satisfaction and progress.

About Peter

I'm Peter Traunmüller, a practically minded electronics engineer with a bunch of ideas for many interesting implementations. There have been various projects I've been developing in the past 10+ years, which you can find on websites like github, reddit, EEVBlog and other forums. My know-how spans from analog circuit engineering and embedded systems programming, over PCB layouting, to manufacturing and testing of all kinds of hardware/software, mechanics and certifications. I also consider C the superior language ;)

About Bianca

My name is Bianca and I'm here for all the non-technical aspects of our operation. I have a big interest in visuals, organization and the nitty-gritty of practically getting things to you. Packaging, layout, shipment and other design elements are my specialty and I think every photo is an important representation of the solutions we offer.

If you have any questions, just shoot us a message!