Bluetooth Wireless Primer

One way to explain Bluetooth is to say that it's a cable replacement technology. If you look around your desktop, you may see the problem. The back of your PC sprouts cables like an overgrown garden. There's a cable going to the monitor, another to the printer, one more to the mouse, and one to the keyboard. Add in speakers, a scanner, an external drive, or who knows what else and your desk can be a maze of cables.

Bluetooth can replace all those cables with a low cost (less than $5) radio chip in each device that allows them to communicate wirelessly. If you want to move the whole system to another desk, you don't have to undo all the cables and figure out what to plug in where at the new place. With Bluetooth, you just move the components and plug them in to the power. They'll send out radio waves to find each other and connect without hassle.

Another way to explain Bluetooth is to say that it's like wireless USB. Your computer probably comes with several USB ports; and if the designers were smart, those ports are in front for easy access. But it can still be a hassle to find a USB cable and hook up your mobile phone, PDA, digital camera, laptop, or whatever else you have that needs to send information to or get information from the desktop PC. If all these devices are Bluetooth enabled, that hassle is gone.

Instead, what you do is take the devices through a simple one time process called "pairing." That means that you're teaching your desktop PC, for example, to "see" and recognize your mobile phone. Ever afterwards, whenever you mobile phone comes within range of the desktop PC, they'll find each other and establish a connection. You don't have to do anything. For added security, you can specify a passkey at the time of pairing so that these two devices check to make sure before allowing the connection.

The standard range of Bluetooth devices is about 10 meters (33 feet). More powerful Bluetooth devices can go 100 meters, but that takes more power and isn't as common. The Bluetooth broadcast can go through walls, so the devices don't have to be in the same room. At the same time, the range isn't extensive enough to allow Bluetooth to replace your Wi-Fi network and cover the entire home or office.

On the other hand, a Bluetooth network, called a "piconet," is completely portable. With Wi-Fi, you're limited by where your router is. That's the device that keeps the network going. With Bluetooth, the network is established on an ad hoc basis whenever two paired devices come within range of each other.

A Bluetooth piconet can consist of one "master" device and up to seven "slaves." But any of these slaves can also participate in another piconet, so you're not limited to 8 devices. You just set up a maximum of 8 devices per piconet and link the piconets together. This is called a "scatternet."

The applications for this technology are just beginning to be explored. One popular application is a wireless headset for a mobile phone.