It appears that not all USB cables (one end: USB, the other end - Micro-USB) are created equal: some can only charge devices (e.g., cell phones, e-readers), others can also sync them.

  1. Are there just 2 kinds? What's the background?
  2. How do I tell one kind from the other without plugging the device?

The difference is in the amount of wires in the cable. Charging-only cables just have two wires in them: power (+5V) and ground. These are often thicker than usual to accomodate the higher charging currents available today (2A+). Needless to say, with just power connected you cannot transfer any data over such a cable.

Sync cables - like any other USB cable - have all four wires implemented: Power, ground and two data lines (D+ and D-, a differential pair). These are usually, but not always, thinner than charging cables and usually designed for currents up to 900mA.

  • Thanks! Are there any markings on the cables which identify which kind they are? – sds Aug 10 '14 at 14:41
  • There is no universally agreed upon logo that distinguishes them, but charging-only cables usually have an identifying mark on the micro USB-end - e.g. my charging cables have a 'B' on the molding - whereas data cables have the USB logo on both ends. – user36129 Aug 10 '14 at 14:46

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.