Bluetooth is a rapidly evolving wireless data transmission technology, its development was initiated by the market leaders in data transmission and the computer industries, including Ericsson, Intel, IBM, Nokia, and Toshiba. Further, several other companies, including: Microsoft, Motorola and Lenovo, have become new members of the Bluetooth Special Interest Group.
The name Bluetooth was given to this technology in honor of the Danish King from the 10th century - Harald Blatan (Blatan means Blue Tooth in Danish).
In the 10th century, Danish King Harald II Blatan became famous for his ability to find a common language with numerous Danish vassals, and to unite them. After more than 1000 years, the name of the famous Danish king was chosen for the wireless Bluetooth technology. The Swedish company Ericsson, one of the initiators of the Bluetooth project, is claimed to have recommended that name.
This advanced technology allows various devices, including laptops, PDAs, cell phones, and many other devices, to communicate with one another automatically, and to exchange information between one another. One device can communicate with up to 7 other Bluetooth devices simultaneously, while the rest of the devices will be in a standby mode. The devices use a free licensing ultra-high frequency - 2.4 GHz. This is the operating range for local radio stations with WLAN (IEEE 802.11) standard, and other common devices and appliances.
Bluetooth provides an up to a 721 kbit/s data transfer rate, within a radius of up to 10 - 20 meters (33-66 feet) depending on the chip-set and power.
FHSS (Frequency Hopping Spread Spectrum) technology allows switching from one operating frequency to another on the pseudo-random algorithm (up to 1600 conversions per second), in order to maintain a stable noise-secure communication. With the interaction of several Bluetooth devices, one of them becomes a principal device, which manages the frequency and synchronization, while the other devices (up to 7) are subordinate to the first one. If there are more devices, they will automatically form an additional network. Each Bluetooth element has its unique 48-bit address.
Frequency Hopping Spread Spectrum technology (FHSS) increases security of the system against noises and disturbances, as well as against unauthorized interception of the transmitted information. There are 3 main levels of protection: no special protection, password protected access to registered devices, and information protection by a 128-bit key.
Unlike IrDA, which requires the devices to be aimed at each other (within the limits of visibility of up to 1-2 meters), Bluetooth uses radio waves that can pass through walls and non-metallic barriers.
Motorola, Ericsson, Nokia and other companies have invested a lot of their money in this technology, and not in vain. Bluetooth technology has achieved widespread distribution, and billions of Bluetooth devices took their places in our lives.