What is... USB

A guide to understanding USB and USB devices

Author:  Paul Landers

USB (Universal Serial Bus) is a connection standard for external devices (or peripherals) to be connected to computers. In time, it's hoped that USB will replace most of the serial and parallel connections on computers. The USB standard is controlled by a Standards body consisting mainly of computer hardware manufacturers. In my mind, USB is one of the better things to happen to computing technology over recent years.

USB cables come with plugs and USB devices come with receptacles. There are different sizes of USB connectors, usually depending on the size of the device. There's Type A, Type B, Mini USB and Micro USB. USB devices and cables are easily identified by the USB logo clearly visible on the packaging.

At this time there are 2 speeds available in USB, USB 1.1 and USB 2.0 (usually referred to as "Hi Speed" USB). USB 1.1 transfers information at speeds up to 12 Megabits per second while USB 2.0 transfers information at up to 480 Megabits per second. You can read a more detailed article about Bits and Bytes here. To get full USB 2.0 performance, you must connect a USB 2.0 device to a USB port that supports USB 2.0. You can connect a USB 1.1 device to a USB 2.0 port or a USB 2.0 device to a USB 1.1 port, but you will only get USB 1.1 performance.

In theory, you can connect up to 127 devices to each USB Host. To get access to additional USB ports, you simply get an additional USB "Hub". A USB Hub is a device with one port which connects to your computer (or another Hub) and two or more device connection ports (they usually come with 4 or more). Hubs are relatively inexpensive and a good way to expand your computer system's capabilities.

These days most computer peripheral devices come with USB connectivity - printers, keyboards, mice, Hard Disk Drives, Web cameras, speakers etc. USB provides an easy way to add components without having to open your computer. USB can even be used to "charge" or "power" low-power devices such as mobile phones and MP3 players.

One of the great benefits of USB is that you can plug and unplug a device from your computer without having to shut your computer down. It provided us with true "plug and play" performance (rather than the old plug and pray!).

When installing a new USB device to your computer for the first time, make sure you read the manufacturer's instructions first. Some devices require that the software be installed first while others require the software to be installed with the device plugged-in.

Another great thing about USB is that it has allowed USB Flash Drives to proliferate. In case you've never heard of one, a USB Flash Drive is another form of information storage. It's a tiny device (and getting smaller each day), available in varying capacities from 64 MegaBytes to 8 GigaBytes (just released as at the time of writing this article).

USB Flash Drives simply plug in to an USB port and are seen by your computer as another storage drive (like your Hard Disk Drive). As such, they generally need no special software to operate. Being another storage drive means that you can simply "drag and drop" files and folders to a Flash Drive for safekeeping, transportation etc. A Flash Drive has no moving parts and so is more robust than a disk drive. It's far more convenient for keeping information than burning a CD or DVD. USB Flash Drives generally come with an inbuilt USB plug, so there are no cables to worry about.

If you regularly transport information from one computer to another or if you are looking for a convenient way to backup or safekeep information, consider purchasing a USB Flash Drive. They're relatively inexpensive and excellent value for money.

A typical USB Flash Drive - small enough to attach to a keyring