Bluetooth Technology.

Bluetooth, named after the renowned Danish King, Harold Bluetooth, is a short-range wireless connectivity standard.

• Bluetooth is capturing the minds of the present day technologists, as a technology enabler for the wireless unification of a wide variety of portable devices like mobile PCs, mobile phones and the like. It does away with the cables and enables voice and data transfer between the devices through wireless networks called piconets.
  The primary segments identified for Bluetooth application are: Cellular & PCS Mobile Phones, Digital Cordless Phones, Data Access Points, PC Cards and Adapters , Notebook & Desktop PCs, Handheld PCs & Palm Companions / PDA s, Digital Still Cameras, Output Equipment, Automotive and Industrial & Medical applications.
  The technology behind it:
  Bluetooth is a Radio Frequency (RF) specification for short-range, point-to-multi-point voice and data transfer. An advantage of Bluetooth is it's similarity to many other specifications already deployed and it's borrowing of many a feature from these specifications. The 2.4GHz band is used by IEEE 802.11 to enable wireless LAN connectivity. Bluetooth borrows specifications to enable file sharing and data transfers between devices from IrDA (a wireless specification that uses InfraRed light to connect devices). HomeRF SWAP, a specification aimed at small network of devices for the home environment, is another source for Bluetooth.
  It is omni-directional and has a present nominal link range of 10cm to 10m, which can be extended to 100m, with increased transmitting power. Bluetooth operates in the 2.4GHz Industrial-Scientific-Medical (ISM) Band and uses a Frequency Hop (FH) spread spectrum technology in which packets are transmitted in defined time slots on defined frequencies. A full duplex information interchange rate of upto 1Mbps may be achieved in which a Time-Division Duplex (TDD) scheme is used.
  A Bluetooth System:
  
• A Radio Unit - consisting of a radio transceiver, which provides the radio, link between the Bluetooth devices.
• A Baseband Unit - a hardware consisting of flash memory and a CPU. This interfaces with the radio unit and the host device electronics.
• Link Management Software - a driver software or firmware which enables the application software to interface with the baseband unit.
• An Application Software - this implements the user interface and is the application that can run on wireless.

BLUE TOOTH USAGE MODELS

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  The usage model being presented below are those which have been identified by the Bluetooth SIG's marketing group and helps us to get a peep into the vast areas of application of this wonderful standard.
  
• The three-in-one phone: It can work as cordless phones connecting to the public switched telephone network at home and office and thus incurring the fixed line charge. It could function as a walkie-talkie with other telephones in the same office or building, without incurring any charge. This telephone can also connect to the cellular infrastructure and function as a cellular phone, incurring cellular charges. At home, your phone functions as a portable phone (fixed line charge). When you're on the move, it functions as a mobile phone (cellular charge). And when your phone comes within range of another mobile phone with built-in Bluetooth wireless technology, it functions as a walkie-talkie (no telephony charge).
• The Internet Bridge: In this usage model, mobile phone or cordless modem functions as a modem to the PC, providing dial-up networking and fax capabilities without a need for physical connection to the PC. Use your mobile computer to surf the Internet wherever you are, and regardless of whether you're cordlessly connected through a mobile phone (cellular) or through a wire-bound connection (e.g. PSTN, ISDN, LAN, xDSL).
• The Interactive Conference: Here, multiple data terminals, use a Local Access Network (LAN) access point as a wireless connection to a LAN. Once connected, the data terminals operate as if they were connected to the LAN via dialup networking. The terminals can access all of the services provided by the LAN. In meetings and conferences you can transfer selected documents instantly with selected participants, and exchange electronic business cards automatically, without any wired connections.
  The file transfer usage model offers the ability to transfer data objects from one device to another. Object types include, among others, ***.xls,***.ppt,***.wav,***.jpg,***.doc files or entire folders, directories or streaming data formats. Also, this offers a possibility to browse the contents of the folders on a remote device.
• The Ultimate Headset: The Headset, can be wirelessly connected for the purpose of acting as a remote device's audio input and output interface .The headset increases the freedom of movement while maintaining privacy. The headset can be typically used with a cellular headset, cordless handset or personal computer for audio input and output. This headset will also have the ability to answer incoming calls and then terminate them without physically manipulating the telephone handset.
  Connect your wireless headset to your mobile phone, mobile computer or any wired connection to keep your hands free for more important tasks when you're at the office or in your car.
• The Automatic Synchronizer: This provides a device-to-device synchronization of the personal information management (PIM) information. Synchronization requires business card, calendar and task information to be transferred and processed by computers, cellular phones and PDA s, utilizing a common protocol and format. This involves, automatic synchronization of your desktop, mobile computer, notebook (PC-PDA and PC-HPC) and your mobile phone. For instance, as soon as you enter your office, the address list and calendar in your notebook will automatically be updated to agree with the one in your desktop, or vice versa.

IrDA AND BLUETOOTH IrDA-Data (IrDA -> Infra-red Data Association) is another short-range wireless connectivity standard with an installed base of 50 million units, by now. IrDA is a point-to-point, narrow angle (30 degree cone), ad-hoc transmission standard designed to operate over a distance of 0 to 1 meter and at speeds of 9.6kbps to 4Mbps, which is expected to increase to 16Mbps.
While the application areas of Bluetooth and IrDA overlap, they are not competitive standards, necessarily. The short range, narrow angle of IrDA allows the user to aim, in point-and-shoot style at a targeted recipient, for example in a conference hall. Close proximity to the other person is natural in a business card exchange situation and the short range is an advantage of IrDA for such applications.
The directional nature of IR enables a low level security because of direct line-of-sight nature; but it provides for, no security at the link level. There are security loopholes as it is possible to eavesdrop on a conversation by detecting reflected light and filtering out the surrounding ambient noise.
In contrast, Bluetooth addresses the security concerns by providing authentication and encryption in its baseband protocol. Authentication relies on a challenge-response protocol utilizing a secret key, personal identification number or PIN. Bluetooth devices talking to one another should have the same PIN. The protocol allows each device to authenticate the other. After the devices are authenticated it is possible to encrypt the transmission for added security.
Thus, it is expected that while in some devices both IR and Bluetooth may co-exist, for the other applications, the choice of Bluetooth and IR will be based on the applications and required usage models.
Mind-boggling technology like the Bluetooth and GPRS, is on its way to make communications in the future, a completely different ball game. A ball game with a win-win situation.