02-06-2012, 01:11 PM
Bluetooth wireless technology
[attachment=23986]
INTRODUCTION:
Bluetooth wireless technology is a short-range communications technology intended to replace the cables connecting portable and/or fixed devices while maintaining high levels of security. The key features of Bluetooth technology are robustness, low power, and low cost. The Bluetooth Specification defines a uniform structure for a wide range of devices to connect and communicate with each other.
The structure and the global acceptanc of Bluetooth technology means any Bluetooth enabled device, almost everywhere in the world, can connect to other Bluetooth enabled devices located in proximity to one another.
It was taken from the 10th century Danish King Harald Blatand who unified Denmark and Norway.
Bluetooth uses a radio technology called frequency-hopping spread spectrum, which chops up the data being sent and transmits chunks of it on up to 79 bands (1 MHz each) in the range 2402-2480 MHz. This range is in the globally unlicensed Industrial, Scientific and Medical (ISM) 2.4 GHz short-range radio frequency band. Bluetooth provides a secure way to connect and exchange information between devices such as faxes, mobilephones, telephones,laptops, personal computers and video game consoles.
Specifications and features:
The Bluetooth specification was developed in 1994 by Jaap Haartsen and Sven Mattisson, who were working for Ericsson in Lund, Sweden. The specification is based on frequency-hopping spread spectrum technology. The specifications were formalized by the Bluetooth Special Interest Group (SIG). The SIG was formally announced on May 20, 1998. Today it has a membership of over 13,000 companies worldwide. It was established by Ericsson, IBM, Intel, Toshiba, Motorola andNokia, and later joined by many other companies.
The Bluetooth Special Interest Group (SIG) is a privately held, not-for-profit trade association founded in September 1998. The Bluetooth SIG itself does not make, manufacture, or sell Bluetooth enabled products. The SIG member companies are leaders in the telecommunications, computing, automotive, music, apparel, industrial automation, and network industries. SIG members drive development of Bluetooth wireless technology, and implement and market the technology in their products. The main tasks for the Bluetooth SIG are to publish Bluetoothspecifications, administer the qualification program, protect the Bluetooth trademarks and evangelize Bluetooth wireless technology.
The Bluetooth SIG global headquarters are in Kirkland, Washington, USA and has local offices in Hong Kong, Beijing, China, Seoul, Korea, Minato-Ku, Tokyo, Taiwan and Malmo, Sweden.
Bluetooth is a packet-based protocol with a master-slave structure. One master may communicate with up to 7 slaves in a piconet; all devices share the master's clock. Packet exchange is based on the basic clock, defined by the master, which ticks at 312.5 µs intervals. Two clock ticks make up a slot of 625 µs; two slots make up a slot pair of 1250 µs. In the simple case of single-slot packets the master transmits in even slots and receives in odd slots; the slave, conversely, receives in even slots and transmits in odd slots. Packets may be 1, 3 or 5 slots long but in all cases the master transmit will begin in even slots and the slave transmit in odd slots.
Communication and connection:
A master Bluetooth device can communicate with up to seven devices in a piconet. The devices can switch roles, by agreement, and the slave can become the master at any time. At any given time, data can be transferred between the master and one other device. The master chooses which slave device to address; typically, it switches rapidly from one device to another in a round-robin fashion. Simultaneous transmission from the master to multiple other devices is possible via broadcast mode, but this capability is infrequently used in practice.
The Bluetooth Core Specification provides for the connection of two or more piconets to form a scatternet, in which certain devices serve as bridges, simultaneously playing the master role in one piconet and the slave role in another. Many USB Bluetooth adapters or "dongles" are available, some of which also include an IrDA adapter. Older (pre-2003) Bluetooth dongles, however, have limited capabilities, offering only the Bluetooth Enumerator and a less-powerful Bluetooth Radio incarnation. Such devices can link computers with Bluetooth with a distance of 100 meters, but they do not offer much in the way of services that modern adapters do.
[attachment=23986]
INTRODUCTION:
Bluetooth wireless technology is a short-range communications technology intended to replace the cables connecting portable and/or fixed devices while maintaining high levels of security. The key features of Bluetooth technology are robustness, low power, and low cost. The Bluetooth Specification defines a uniform structure for a wide range of devices to connect and communicate with each other.
The structure and the global acceptanc of Bluetooth technology means any Bluetooth enabled device, almost everywhere in the world, can connect to other Bluetooth enabled devices located in proximity to one another.
It was taken from the 10th century Danish King Harald Blatand who unified Denmark and Norway.
Bluetooth uses a radio technology called frequency-hopping spread spectrum, which chops up the data being sent and transmits chunks of it on up to 79 bands (1 MHz each) in the range 2402-2480 MHz. This range is in the globally unlicensed Industrial, Scientific and Medical (ISM) 2.4 GHz short-range radio frequency band. Bluetooth provides a secure way to connect and exchange information between devices such as faxes, mobilephones, telephones,laptops, personal computers and video game consoles.
Specifications and features:
The Bluetooth specification was developed in 1994 by Jaap Haartsen and Sven Mattisson, who were working for Ericsson in Lund, Sweden. The specification is based on frequency-hopping spread spectrum technology. The specifications were formalized by the Bluetooth Special Interest Group (SIG). The SIG was formally announced on May 20, 1998. Today it has a membership of over 13,000 companies worldwide. It was established by Ericsson, IBM, Intel, Toshiba, Motorola andNokia, and later joined by many other companies.
The Bluetooth Special Interest Group (SIG) is a privately held, not-for-profit trade association founded in September 1998. The Bluetooth SIG itself does not make, manufacture, or sell Bluetooth enabled products. The SIG member companies are leaders in the telecommunications, computing, automotive, music, apparel, industrial automation, and network industries. SIG members drive development of Bluetooth wireless technology, and implement and market the technology in their products. The main tasks for the Bluetooth SIG are to publish Bluetoothspecifications, administer the qualification program, protect the Bluetooth trademarks and evangelize Bluetooth wireless technology.
The Bluetooth SIG global headquarters are in Kirkland, Washington, USA and has local offices in Hong Kong, Beijing, China, Seoul, Korea, Minato-Ku, Tokyo, Taiwan and Malmo, Sweden.
Bluetooth is a packet-based protocol with a master-slave structure. One master may communicate with up to 7 slaves in a piconet; all devices share the master's clock. Packet exchange is based on the basic clock, defined by the master, which ticks at 312.5 µs intervals. Two clock ticks make up a slot of 625 µs; two slots make up a slot pair of 1250 µs. In the simple case of single-slot packets the master transmits in even slots and receives in odd slots; the slave, conversely, receives in even slots and transmits in odd slots. Packets may be 1, 3 or 5 slots long but in all cases the master transmit will begin in even slots and the slave transmit in odd slots.
Communication and connection:
A master Bluetooth device can communicate with up to seven devices in a piconet. The devices can switch roles, by agreement, and the slave can become the master at any time. At any given time, data can be transferred between the master and one other device. The master chooses which slave device to address; typically, it switches rapidly from one device to another in a round-robin fashion. Simultaneous transmission from the master to multiple other devices is possible via broadcast mode, but this capability is infrequently used in practice.
The Bluetooth Core Specification provides for the connection of two or more piconets to form a scatternet, in which certain devices serve as bridges, simultaneously playing the master role in one piconet and the slave role in another. Many USB Bluetooth adapters or "dongles" are available, some of which also include an IrDA adapter. Older (pre-2003) Bluetooth dongles, however, have limited capabilities, offering only the Bluetooth Enumerator and a less-powerful Bluetooth Radio incarnation. Such devices can link computers with Bluetooth with a distance of 100 meters, but they do not offer much in the way of services that modern adapters do.