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Bluetooth is an industrial specification for wireless personal area networks (PANs) first developed by Ericsson, later formalized by the Bluetooth Special Interest Group (SIG), which was formally announced May 20, 1999. It was composed by Sony Ericsson, IBM, Intel, Nokia and Toshiba.
The system is named after a Danish king Harald Blåtand (Harold Bluetooth in English), King of Denmark and Norway from 935 and 936 respectively, to 940 known for his unification of previously warring tribes from Denmark, Norway and Sweden. Bluetooth likewise was intended to unify different technologies like computers and mobile phones. The Bluetooth logo merges the Nordic runes for H and B.
Bluetooth provides a way to connect and exchange information between devices like personal digital assistants (PDAs), mobile phones, laptops, PCs, printers and digital cameras via a secure, low-cost, globally available short range radio frequency.
Bluetooth lets these devices talk to each other when they come in range, even if they're not in the same room, as long as they are within 10 metres (32 feet of each other).
The version shipping currently to consumers as embedded Bluetooth and USB dongles is 1.1.
It is a wireless radio standard primarily designed for low power consumption, with a short range (from 10 up to 100 meters) and with a low-cost transceiver microchip in each device.
It can be used to wirelessly connect peripherals like printers or keyboards to computers, or to have PDAs communicate with other nearby PDAs or computers.
Cell phones with integrated Bluetooth technology have also been sold in large numbers, and are able to connect to computers, PDAs and, specifically, to handsfree devices. BMW was the first motor vehicle manufacturer to install handsfree Bluetooth technology in its cars, adding it as an option on its 3 Series, 5 Series and X5 vehicles. Since then, other manufacturers have followed suit, with many vehicles, including Toyota's 2004 Prius and the 2004 Lexus LS 430, now also featuring Bluetooth technology. The Bluetooth car kits allow users with Bluetooth-equipped cell phones to make use of some of the phone's features, such as making calls, while the phone itself can be left in a suitcase or in the boot/trunk, for instance.
However, the standard also includes support for more powerful longer-range devices suitable for constructing a wireless LAN. Every Bluetooth device can simultaneously maintain up to 7 connections, but only one active connection at the time. These groups (maximum of 8 BT devices, one host 7 slaves) are called piconet. Bluetooth specification also enables a possibility to connect two piconetworks together, when one master device acts as a bridge, but those devices are yet to come (coming with in next two years). Every device can be configured to constantly announce its presence to nearby devices, in order to establish a connection. It is also possible to password protect a connection between two devices, so that no others can listen in.
The protocol operates in the license-free ISM band at 2.45 GHz. It reaches speeds of 723.1 kbit/s. In order to avoid interfering with other protocols which may use the 2.45 GHz band, the Bluetooth protocol divides the band into 79 channels and changes channels up to 1600 times per second.
Bluetooth should not be compared to Wi-Fi, a faster protocol requiring more expensive hardware that covers greater distances and uses the same frequency range. While Bluetooth is a cable replacement creating personal area networking between different devices, Wi-Fi is a cable replacement for local area network access. They serve different purposes.
Many USB Bluetooth adapters are available, some of which also include an IrDA adapter.
Bluetooth devices/modules are increasingly being made available which come with an embedded stack and a standard UART port. The protocol at the UART port can be as simple as the industry standard AT protocol, which allow the device to be configured to act in cable replacement mode. This means, it is now becoming a matter of hours (instead of weeks) to wireless enable legacy products which communicate via an UART port.
The Bluetooth SIG is working on versions 1.2 and 2.0
This version is backwards compatible with 1.1 and the major enhancements include
There is no definitive information about what will be included in 2.0, but some details have been released by Ericsson research scientists:
In April 2004, security consultants revealed a security flaw that makes it possible to crack into conversations on Bluetooth based wireless headsets by reverse engineering the PIN.
This is one of a number of concerns that have been raised over the security of Bluetooth communications. In 2004 the first purported virus using Bluetooth to spread itself among mobile phones for the Symbian OS. The virus was written as a proof-of-concept by Kaspersky Labs and requires users to confirm the installation of unknown software before it can propagate. Because of this, it should not be regarded as a security failure of either Bluetooth or the Symbian OS. It has not propogated 'in the wild'.
Bluetooth uses the SAFER+ algorithm for authentication and key generation.
Versions 1.0 and 1.0B had numerous problems and the various manufacturers had great difficulties in making their products interoperable. 1.0 and 1.0B also had mandatory Bluetooth Hardware Device Address (BD_ADDR) transmission in the handshaking process, rendering anonymity impossible at a protocol level, which was a major set-back for services planned to be used in Bluetooth environments, such as Consumerium.
In order to use Bluetooth, a device must be able to interpret certain Bluetooth profiles. These define the possible applications. Following profiles are defined:
This profile allows to synchronise Personal Information Manager (PIM) items. As this profile originated as part of the infrared specifications but has been adopted by the bluetooth SIG to form part of the main Bluetooth specification, it is also commonly referred to as IrMC Synchronization.
Compatibility of products with profiles can be verified on the .
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