Who hasn’t experienced this? You need to quickly charge your phone, plug it into the charger, and after an hour, it’s only 10% more charged. Or you want to transfer data to your computer, but it doesn’t work? Where’s the problem? Maybe in the cable!
Thanks to this cable tester, I sorted out the cables that were lacking signals. It can test USB-C, USB-A and B, microUSB, Lightning, and more.
Of course, there are plenty of such testers, and I will add some more at the end of the article.
What I like about this one is its absolute simplicity and the ability to test all the most common cables. You just need to connect a 3V CR2032 battery (the board also supports power from a 3-12V adapter) and then just test the cables. The connection of individual signals is indicated by the lighting of LEDs.
The tester also tests the shielding of the cable, but on the other hand, it cannot test e-Marker – that is, active USB cables.
Supported cables are TypeB 3.0, TypeB 2.0, TypeC 3.0/3.1/3.2, MicroB 3.0, MicroB 2.0, MiniB 2.0, and Lightning.
Most Common Missing Signals and Issues (Simplified)
USB-C to USB-C Cable
- Missing CC1/CC2 Wires:
- These wires are used for detecting connection and orientation of the cable, negotiating fast charging via USB Power Delivery (PD).
- If they are missing or improperly connected, the cable will not support PD, so high-speed charging and higher voltage/current (e.g., 20 V/5 A) will not be possible.
- The device will charge more slowly or not at all.
- Missing CC wires also mean that the device may not correctly detect the type of connection, which can lead to connection issues (the cable will not be “seen” as correct).
- Missing VBUS and GND:
- The cable does not carry power, and the device does not charge.
- If GND is improperly connected, it can pose a safety risk and malfunction.
- Missing Data Lines (D+/D- for USB 2.0):
- Without data lines, data cannot be transferred.
- The cable may only function as a power cable, which is a limited use case.
- Missing Data Lines (TX/RX for USB 3.x)
- There is a reduction in the cable’s transmission capacity, sometimes down to half the speed compared to the full capability of USB 3.x (the cable may still work in USB 2.0 mode (D+ and D- lines), but will not support full USB 3.x speeds).
USB-A 2.0 to USB-C Cable
- Missing CC1/CC2:
- The USB-A connector does not have CC signals, so the cable is limited in USB PD functionality.
- Fast charging via USB PD is not possible (USB-A is not designed for PD).
- Fast charging may only be supported via the USB QC (QuickCharge) protocol, or charging operates in basic mode (5 V, current limited according to USB-A specifications).
- Missing VBUS/GND:
- No power will be connected, and the cable does not work at all.
- Missing D+/D-:
- The cable will not support data transfer, only charging.
USB-A 3.x to USB-C Cable
- Absence of CC1 and CC2 Wires on the USB-A Side:
- The USB-A connector does not have CC wires, which prevents support for USB Power Delivery (USB PD).
- Fast charging USB PD or lower power modes specific to USB-C with CC wires are not possible.
- Fast charging may only be supported via the USB QC (QuickCharge) protocol, or charging operates in basic mode (5 V, current limited according to USB-A specifications).
- Data Lines USB 3.x (TX/RX) are Present on USB-A 3.x:
- USB-A 3.x connectors have additional pins for SuperSpeed data lines (transmit and receive) compared to USB 2.0.
- If these wires are broken or missing, data speeds are limited below the USB 3.x standard.
- If these lines are faulty, transmission often gets limited to USB 2.0 (only D+ and D- lines).
- Missing or Faulty VBUS and GND:
- The cable will not be able to power the device.
- Incorrect ground connection can lead to safety risks or malfunction.
I test a USB-C to USB-C cable and only CC1 lights up; when I flip the cable, only CC2 lights up – is this correct?
Yes, that is absolutely correct.
- These wires serve to detect the orientation of the cable (how the cable is connected on both ends, as USB-C is a symmetrical connector).
- When the cable is plugged in one way, the device and host activate the CC1 wire.
- When the cable is flipped 180°, the CC2 wire is activated.
- This allows devices to correctly determine the orientation of the cable and accordingly redirect USB signals, power, and data lines.
Cable Testers
This is the one I bought
And I like these others
An advanced tester, but only for USB-C cables, is this one – https://www.aliexpress.com/.
This one supports both e-Marker detection and short circuit between wires, operating voltage up to 48V, displays current voltage, and can function as a USB PD trigger.
This cheaper one, on the other hand, can only indicate signal connections and is for USB-C cables only – https://www.aliexpress.com/
