Bluetooth is named after the Danish King Harald Blaatand from the 10th century. It was founded by Ericsson, Intel, IBM, Nokia and Toshiba.
Bluetooth provides two types of physical links. The Synchronous Connection Oriented (SCO) and the Asynchronous Connectionless (ACL) link. The SCO is used for voice and the ACL is used for data. Simultaneously up to three synchronous voice channels can be used. The data rate is 432 kbit/sec symmetrically and 721 / 57 kbit/s asymmetrically.
79 channels with 1MHz carrier distance are available. The channels are changed 1.600 times per second (channel hopping). This is a pseudo-random sequence of 79 frequencies.
The maximum transmission power is up to 100 mW. The possible transmission distance is up to 100 meters.
Bluetooth operates in the license free 2.4 GHz range. It is a world-wide open standard that makes the wireless interconnection of different devices from different manufacturers possible.
Bluetooth supports the 'ad-hoc networking'.
Two types of networks are supported: piconet and scatternet.
Piconet is a network consisting of one master and up to seven slaves. Scatternet is a network formed by several piconets.
Between different mobile wireless devices a spontaneous networking and immediate communication is possible.