Bluetooth is a wireless standard developed to allow electronic equipment to make its own connections without action from a user. Bluetooth is intended to be a standard that works at two levels.
             • It provides agreement at the physical level. Bluetooth is a radio frequency standard.
             • It also provides agreement on when bits are sent, how many will be sent at a time, a redundancy check.
             The companies belonging to the Bluetooth SIG (Special Interest Group) aim for Bluetooth's radio communications take the place of wires for connecting peripherals, telephones and computers.
             Bluetooth is intended to get around the problems that come with infrared and other systems. The hardware vendors have developed a specification for a very small radio module to be built into computer, telephone and entertainment equipment. There are four important features to Bluetooth.
             • It is dynamically configurable.
             Bluetooth communicates on a frequency of 2.45 gigahertz, which has been set aside by international agreement for the use of industrial, scientific and medical devices (ISM). A number of devices take advantage of this same radio-frequency band. Baby monitors, garage-door openers and the newest generation of cordless phones all make use of frequencies in the ISM band. Making sure that Bluetooth and these other devices do not interfere with one another is a crucial part of the design.
             Bluetooth uses fast acknowledgement and frequency-hopping operation to make the link stable and without interference. Bluetooth avoids interference from other signals by hopping to a new frequency after transmitting or receiving a packet.
             A Bluetooth-enabled wireless headset for cell phones hit the shelf at about five times the price of competing, non-Bluetooth wireless products. It requires two pieces of hardware for the point-to-point network: a Bluetooth base uni
             ...