Leave the Wires Behind

Bluetooth is a technology for wireless communication between devices. It's based on a low-cost short-range radio link.

The advantages of Bluetooth

Every decorator knows that cables and wires are unsightly and confusing. Bluetooth connections allow wireless communication between devices within a range of about 30 feet (10 meters). Unlike infrared, you don't have to point devices directly at each other, or even have both devices in the same room. Bluetooth can initiate connections automatically with paired devices, so you don't even have to think about it. And no, you don't have to pay for a Bluetooth connection, no matter how much data you transfer.

See examples of what you can do >>

How it Works

When two devices share information, there are a few things that have to be worked out: firstly, how they will physically connect - through how many wires? Or none at all? - and then, what are the agreed commands that will make sense to both devices (the protocol)? Bluetooth is an industry standard that solves both of these issues cheaply, and using very little battery power.

Cheap Little Chips

A Nokia phone supporting Bluetooth contains a tiny, inexpensive radio chip, which is designed to send data over a specific radio frequency to another Bluetooth chip. The receiver chip, whether it's in a PC, phone, or other device, then transmits the data to the receiving device. The chips are easy to make and the entire process is very low on power consumption, so it's no surprise that Bluetooth has become a wireless industry standard.

Bluetooth communicates over radio waves on a frequency of about 2.45 gigahertz. This is the same band used by many industrial and medical devices as well as some household ones, such as garage door openers and baby monitors.

Electronic Conversations

When two devices running Bluetooth come into range of each other, a little electronic conversation happens. They decide whether or not the devices need to share data and if they do, they form a little network - usually you don't have to do anything. This is what happens when you use a Bluetooth-enabled Nokia headset or car kit.

When you send data from one phone to another, however, it's a bit different. The person on the receiving end has to accept the transfer, and there may be a password involved. These measures are for privacy and security reasons. Read more on Bluetooth and security at Nokia >>

Voice, Data, and Audio

It's not just little packets of data that can be sent between two Bluetooth devices. Bluetooth also supports voice and audio connections (it is a radio wave, after all).

Avoiding Interference

So in one room of your house you have a stereo system that uses Bluetooth technology instead of cables, a new cordless phone model, a baby monitor, your phone, and a PC. Why don't they interfere with each other?

This is one of the neater things about the Bluetooth design. When we said it operates over a frequency of 2.45 GHz, we actually meant from about 2.40 to 2.48 gigahertz. In this range there are 79 radio frequency channels, and a Bluetooth device skips randomly between these 79 channels 1600 times per second! When two or more devices are connected, they jump around in sync. If two different "conversations" land on the same RF channel at the same time, the interference time is so short that it doesn't cause any problems.

Want more? Get all the technical info you could want at www.bluetooth.org