Personal Area Network.

Using wireless networking with your personal gadgets is often called PAN, which stands for Personal Area Network. The idea is that, in the future, we'll all have laptop computers with their batteries charged and no more need to connect any wires to them at all -- you just place your Bluetooth device near the computer, and the computer sees it and can use it straightaway.

Bluetooth has been around and in-use since 1999, and it's only getting more popular. It was designed to be secure, low cost, and easy to use from day one.

There are two classes of Bluetooth that are in popular use: class 1 and class 2. Class 2 is the most common and cheaper standard, allowing you to use a device that is up to 10 metres (32 feet) away. Class 1 is rarer, but you can still find devices that use it easily enough, and it has ten times the range: 100 metres or 320 feet.

How Does It Work?

Bluetooth is more flexible than 802.11 wireless networking, in exchange for the shorter range. Essentially, a Bluetooth-enabled computer has one Bluetooth receiver installed in it, and this receiver can then be used with up to 7 nearby Bluetooth devices. On the other end, wireless devices do not need to have Bluetooth installed if they support it -- it is already integrated.

Like 802.11, Bluetooth works by using radio signals to create bandwidth. It is not, though, the same thing as an old-style wireless mouse or keyboard, which required a receiver to be plugged into one of your computers' ports, and didn't have range or stability anywhere near that of Bluetooth.

Many computers now come with built in Bluetooth, especially Apple Macs. If you want to add Bluetooth to a computer that doesn't come with it pre-installed, you should probably use a USB to Bluetooth adapter, although internal Bluetooth devices to install in your computer are available. If you have a laptop and a spare PCMCIA slot, you can get Bluetooth cards for that too.

What Can You Do With Bluetooth?

Mobile phones with Bluetooth are very popular, and so are PDAs -- the instant synchronisation of addresses and calendars to a computer is a useful feature. Other than that, almost anything that would usually use USB can be done using Bluetooth, including digital cameras, mp3 players, printers, and even mice and keyboards. If you take a look through the comprehensive list of Bluetooth 'profiles' (kinds of devices that could, in theory, be Bluetooth enabled), it includes cordless phones, faxes, headsets, and even video.

Basically, more than anything, Bluetooth is a replacement for USB: some say that while 802.11 wireless networking is wireless Ethernet, Bluetooth is wireless USB.

Not Just for Computers.

Part of the power of Bluetooth is that it isn't just used to connect things to computers -- it can be used to connect almost anything to anything else, if both things are Bluetooth-enabled and recognise each other.

Mobile phones, in particular, take advantage of this. Hands-free headsets often use Bluetooth to communicate with the phone. Some cars, for example, now have on-board computers that will connect with a Bluetooth phone and allow you to make hands-free calls, regardless of where the phone is in the car (even if you've left it in your bag in the trunk!)

On top of that, of course, Bluetooth devices can communicate with each other. This has led to some people sending messages from their Bluetooth PDAs to others in close range -- not an especially useful feature, but quite fun. This is called 'bluejacking', and the first recorded instance of it was a man who sent a Bluetooth message to another man's Nokia phone while they were in a bank together. What did the message say? 'Buy Ericsson'.

Since then, it has become possible to send images by bluejacking, and it is widely believed to be the newest advertising medium -- yes, it lets billboards send messages to your phone, a practice known as 'bluecasting'. Whether you think that's cool or annoying, of course, is your choice.