Most network protocols just provide channels between communicating enti- ties and let application designers figure out what they want to use them for. For example, 802.11 does not specify whether users should use their notebook com- puters for reading email, surfing the Web, or something else. In contrast, the Bluetooth SIG specifies particular applications to be supported and provides dif- ferent protocol stacks for each one. At the time of writing, there are 25 applica- tions, which are called profiles. Unfortunately, this approach leads to a very large amount of complexity. We will omit the complexity here but will briefly look at the profiles to see more clearly what the Bluetooth SIG is trying to accomplish Six of the profiles are for different uses of audio and video. For example, the intercom profile allows two telephones to connect as walkie-talkies. The headset and hands-free profiles both provide voice communication between a headset and its base station, as might be used for hands-free telephony while driving a car