How to choose a good USB data and charging cable for your mobile phone?

Most of us will have a few USB data and charging cables for our mobile phone, i.e. one at home, one in office, one carrying together with our laptop, etc.

Do you encounter the problem of slow charging, or worst still, unable to charge with the additional USB cable that you bought? Perhaps you can find the solution after reading this.

First of all, although most of the USB cables look alike from their external appearance, they might be different inside the cable, and probably that is the ready why certain USB cable unable to charge your mobile phone, certain can charge but at a very slow rate, certain just work as fine as the original USB cable that come with your phone, and certain even can charge faster than the original cable.

There are 5 wires inside the USB 1 and USB 2 cables, and there are more inside USB 3.0 cable. Since most of the mobile phones nowadays are using USB 2.0 connector, so USB 3.0 is out of our topic here.

The 5 wires are:

• 2x 28 AWG data lines
• 2x 20-28 AWG power conductors
• 1x drain wire

and those 5 wires are connected to the 5 pins in your micro-USB connector.

In fact, there are two kinds of USB cable: fully-rated and sub-channel. The main difference between them is that fully-rated cable can be used for typical peripherals operating at the rate of 480 Mbps (high speed) signalling, while the sub-channel one at the rate of 1.5 Mbps (standard speed) signalling. The construction inside the cable fully-rated and sub-channel cable is different.

As you can see from the diagram above, the fully-rated USB cable is shielded by braid and aluminium foil.

You can probably see some printed codes on the good quality USB cable, including something like this: "28AWG/2C and 24AWG/2C" or "28AWG/1P + 24AWG/2C".

The first code is normally the specification of the data signal pair, which is normally 28AWG. "2C" means 2 conductors, and "1P" or "1Pr" means 1 pair. "2C" and "1P" are basically the same.

The important part is the second code, which is the specification of the power distribution pair. The minimum requirement is 28AWG, and the lower the AWG number the better. This is because lower AWG wire is thinker, and therefore the electrical resistant is lower.

Therefore, charging with a "28AWG/1P + 28AWG/2C" USB cable is normally slower than a "28AWG/1P + 24AWG/2C" cable.

Certain USB cable comes with a ferrite bead at one end, which function is to filter high frequency noise to improve signal transfer

As a conclusion, when you buy additional USB cable to charge your mobile phone, you should look for:

• USB 2.0 support
• High speed 480 Mbps data transfer rate
• The packaging mentions it is a "charging" cable and not only a "data" cable
• Power conductors of 24AWG/2C or better (for faster charging speed)
• (optionally) the ferrite bead

Remember not to only look for the information on the packaging of the cable. Sometimes you will find the specification printed on the cable is different from that mentioned on the packaging.