Linux Unwired [Electronic resources] نسخه متنی

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 support and require more
involvement from the user. User-level applications that support
Bluetooth on Linux are of varying maturity: applications simply
requiring an emulated serial port work out of the box, whereas
specialized Bluetooth tools are under heavy development.

This chapter first introduces the core Bluetooth concepts that will
aid a Linux system administrator in his deployment, discusses kernel
configuration and system-level tools, and finally covers user-level
applications.