Linux Unwired

Chapter 7. Bluetooth

Bluetooth is a wireless cable-replacement technology that uses low-power signals in the 2.4 GHz band. Using Bluetooth, devices can transfer up to 720 kbps. This bandwidth is restricted in comparison to those obtainable from 802.11 wireless technology, and while networking is one application of Bluetooth, it is not the primary application area.

Bluetooth’s goal is to be a low-cost, low-power, and, above all, pervasive technology. As well as to increase convenience for the user, its aim is also to reduce the cost to the manufacturer by eliminating the need to supply cables with devices. As opposed to single-use cables, a Bluetooth transceiver sustains multiple connections, and, for most applications, the bandwidth constraints are not an issue.

As befits a cable-replacement technology, many of Bluetooth’s applications are in areas where infrared, USB, or serial connections were previously used: in connecting peripherals, PDAs, cell phones, and other portable devices. One much-trumpeted application that bucks this general trend is mobile phone headsets, which use Bluetooth to carry the audio to and from the user, who is liberated from the tiresome cable.

Support for Bluetooth in the Linux kernel is mature, being present in both the 2.4 and 2.6 series of stable kernels. Popular core functions of Bluetooth, such as emulated serial connections and networking, are well-supported. More recent Bluetooth technologies, such as keyboard and mice support, have less well-developed ...