The majority of computers have a number of USB ports on the front or back (for a desktop) or the sides (for a laptop). It stands for universal serial bus, and essentially it acts as a communications interface between your computer and whatever device you have plugged into it. 

The problem is that the vast majority of devices that you might wish to use will have a different type of output. Essentially, they speak a different language from other devices of the same type, perhaps because the manufacturer has them using their own special language.

This situation is a nightmare for PC developers, because it means that the computer is expected to understand all of those many different languages, and provide plugs for them too. USB was developed to overcome this, as it is a single standard that your PC is able to speak to your device. Only the plugs differ from device to device, with the smaller devices using the mini or micro sized plugs because of space considerations.

USB is an incredibly useful interface, thanks to its versatility. USB ports can operate input and output devices, hence can accept keyboards and mice, and can run smaller, secondary monitors. They are excellent for transferring data, both onto and off of an external device.

There are are also different speeds available for USB ports. USB 1.0 is the slowest, 2.0 is considered high speed. Version 3.0 is currently still little used. For a particular speed to be achieved, both the PC and the device it is connect to must be able to run at the same speed-if one is capable of 1.0 and the other can do 2.0 then both will run at 1.0. The differences in speed between USB 1.0 and 2.0 can be stark, and this means that devices that will need to transfer a large amount of data are better off when run on 2.0.

Many USB ports are powered, though a few are not. A powered port can be used to charge mobile phones, PDAs and tablet computers, and to run a few other devices such as a USB powered fan. There are other, more unusual USB devices such as toys, and even a USB powered mini fridge!

Data transfer is an important function, and allows you to download photos and videos from either a cell phone or camera, and to upload videos, music, applications and other items onto a smartphone, MP3 player or even some of the hand held gaming devices, or data to or from a flash drive.

Importantly though, it can do both data transfer and power a device at the same time. This allows the running of external hard drives that don’t have their own power supply. By drawing their power through USB they remain incredibly portable and useful for carrying huge files from computer to computer, as well as backing up computers and other USB capable devices.

When you consider the fact that USB will also allow you to run a keyboard, mouse, or other controller on your computer too, it just goes to show how incredibly versatile this interface is.