Upgrading and Repairing Networks

Chapter 22. Bluetooth Wireless Technology

SOME OF THE MAIN TOPICS IN THIS CHAPTER ARE

The Bluetooth Special Interest Group (SIG) 333

General Overview of Bluetooth 333

Piconets and Scatternets 335

Bluetooth Device Modes 338

SCO and ACL Links 339

What Are Bluetooth Profiles? 340

Bluetooth Is More Than a Wireless Communication Protocol 345

The preceding few chapters have covered the various versions of Wi-Fi (802.11a, IEEE 802.11b, and 802.11g), which are the three major contenders for the wireless networking market. Both of these technologies have trade organizations whose purpose is to advance their technology for the markets they target. The 802.11 wireless protocols aim for a market ranging from the home to the workplace to public spaces such as airports, malls, and just about anywhere you can use a cell phone today. The goal of the 802.11 protocols is to provide a worldwide standard that enables you to use a single wireless network adapter card in many different environments.

Bluetooth is another matter altogether. Bluetooth technology was originally designed to replace wires, and for only short distances. The original expectations for Bluetooth were that it would be used to connect such things as a keyboard, mouse, computer, and possibly mobile phone. It was not designed, from the start, to be a wireless networking solution that would span any great distance. Other technologies, such as Wi-Fi and 802.11a, were expected to cover that territory, giving mobile clients easy access to a network. In the home arena, this means that a single Internet connection can be shared by numerous wireless clients (computers, printers, gaming devices). In the work environment, Access Points can allow a mobile user to quickly connect to the corporate cabled network anywhere that a wireless Access Point has been placed. For the business and residential user, it's possible that one or the other of these standards will allow you to open your laptop in a coffee shop, an airport, or some other public space and instantly connect to an Internet provider.

Bluetooth has been in development for several years and despite numerous delays and, for a while, slow uptake into consumer markets, it does now have a decent head of steam going in terms of adoption. When the second edition of this book was written, it was expected to be the hottest new technology of the year. That didn't quite happen. Over the next few years the specifications were further defined, and short-distance networking became part of Bluetooth. Other profiles (which are discussed later in this chapter) were added so that Bluetooth became a practical solution for short-distance networking for many types of consumer and computer devices today. One might say that Bluetooth has finally arrived.

There are two good reasons to consider using Bluetooth to create a small wireless network although 802.11b and 802.11a are now readily available. First, as was the original intent, Bluetooth enables devices, ranging from keyboards and mice to headsets for cellular telephones to make short-distance wireless connections to base PCs and other devices. You can also use this technology for networking computers (such as laptops) over short distances. This is the same capability that 802.11b (Wi-Fi) gives you.

Second, Bluetooth radio chips are inexpensive to manufacture, so you can expect to see them in many other devices in the next few years. And this includes not just computers and communications between computers and computer peripherals, but also many other consumer devices. At this time wireless networking based on the 802.11 specifications are pretty much limited to computers. You can't plug a PCI or CardBus network adapter into your cell phone yet. But you can do this with Bluetooth.

The Bluetooth wireless technology is

• A short-range, lower-power wireless technology

• A means to replace cables, such as those that connect your keyboard, mouse, printer, and other standard computer peripherals

• A protocol that uses a very inexpensive radio transmitter compared to other wireless protocols

• A method to allow data communications between diverse devices such as computers, mobile phones, network appliances, handheld devices, digital cameras, and other consumer devices

This chapter takes a quick look at Bluetooth because even though it might have failed to reach the over-hyped expectations of a few years ago, it has filled a needed and useful role in networking devices over short distances.