Bluetooth
A wireless personal area network (WPAN) standard for short-range transmission of digital voice and data. Using omnidirectional radio waves, Bluetooth transmits through walls and other non-metal barriers. It is widely used for hands-free conversations: countless cellphones are connected to Bluetooth headsets, and numerous vehicles contain Bluetooth-enabled audio systems.
Although the term became nearly synonymous with cellphone headsets, Bluetooth is used in many areas including cellphone to computer transmission and wireless keyboards, mice and game controllers. See WPAN.
Specifications
Supporting point-to-point and multipoint applications (see piconet), Bluetooth provides 1 Mbps transmission, while Bluetooth 2.0 + EDR (Enhanced Data Rate) increased speed to 3 Mbps. Class 1 devices have a maximum power rating of 100 mW over a range of approximately 100 meters. Class 2 devices span 10 meters at 2.5 mW, while Class 3 transmits within one meter at 1 mW. Future versions of Bluetooth are expected to use UWB transmission (see WiMedia Alliance and UWB).
Governed by the Bluetooth Special Interest Group (www.bluetooth.com), founded in 1998 by Ericsson, IBM, Intel, Nokia and Toshiba, Bluetooth transmits in the unlicensed 2.4 GHz band. It uses a frequency hopping spread spectrum technique that changes its signal randomly to one of 79 channels 1,600 times per second. If there is interference from other devices, transmission continues, but speed is downgraded. However, Bluetooth 2.0 + EDR avoids channels that are interfering with other wireless devices.
Bluetooth is also standardized by the IEEE under its wireless personal area network (WPAN) category (see 802.15).
Wibree - Ultra Low Power (ULP) Bluetooth
In 2007, Nokia's Wibree technology was added to Bluetooth and renamed ULP Bluetooth. Using up to a quarter of the power of Bluetooth at 1 Mbps, Wibree enables wireless connectivity to sensors, wristwatches and toys with tiny batteries as well as to larger devices that must conserve power. A dual-mode device, such as a dual-mode phone, is required for both Bluetooth and Wibree connectivity.
King Blatan of Denmark
The name Bluetooth comes from King Harald Blatan (Bluetooth) of Denmark, who in the 10th century, began to Christianize the country. Ericsson, a Scandinavian company, was the first to develop the specification. See Bluejacking, Bluesnarfing, Bluespamming, Bluebugging, Car Whisperer, Bluetooth virus, Cabir, personal area network, wireless adapter and wireless LAN.
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| Two Wireless Systems |
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| Bluetooth became synonymous with cellphone headsets, such as this unit from Cardo Systems (www.cardowireless.com). Two wireless technologies are used with headsets: Bluetooth between ear and cellphone and CDMA or GSM between cellphone and cell tower. |
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| The Bluetooth Logo |
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| The stylized "B" displayed on this cellphone indicates that it has been synchronized with a Bluetooth device. |
| (protocol, standard) | Bluetooth - A specification for short-range radio
links between mobile computers, mobile phones, digital
cameras, and other portable devices.
http://bluetooth.com. | |