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Etymology

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The name “Bluetooth” was proposed in 1997 by Jim Kardach of Intel, who developed a system that would allow mobile phones to communicate with computers. At the time of this proposal, he was reading Frans G. Bengtsson's historical novel The Long Ships about Vikings and the 10th-century Danish King Harald Bluetooth. Bluetooth is the Anglicised version of the Scandinavian Blåtand / Blåtann (or in Old Norse blátǫnn ). It was the epithet of King Harald Bluetooth who united dissonant Danish tribes into a single kingdom, the implication being that Bluetooth unites communication protocols. Logo edit The Bluetooth logo is a bind rune merging the Younger Futhark runes  (ᚼ, Hagall) and  (ᛒ, Bjarkan), Harald's initials.
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Etymology

Image
The name “Bluetooth” was proposed in 1997 by Jim Kardach of Intel, who developed a system that would allow mobile phones to communicate with computers. At the time of this proposal, he was reading Frans G. Bengtsson's historical novel The Long Ships about Vikings and the 10th-century Danish King Harald Bluetooth. Bluetooth is the Anglicised version of the Scandinavian Blåtand / Blåtann (or in Old Norse blátǫnn ). It was the epithet of King Harald Bluetooth who united dissonant Danish tribes into a single kingdom, the implication being that Bluetooth unites communication protocols. Logo edit The Bluetooth logo is a bind rune merging the Younger Futhark runes  (ᚼ, Hagall) and  (ᛒ, Bjarkan), Harald's initials.
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Implementation

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Bluetooth operates at frequencies between 2.402 and 2.480   GHz, or 2.400 and 2.4835   GHz including guard bands 2   MHz wide at the bottom end and 3.5   MHz wide at the top. This is in the globally unlicensed (but not unregulated) industrial, scientific and medical (ISM) 2.4   GHz short-range radio frequency band. Bluetooth uses a radio technology called frequency-hopping spread spectrum. Bluetooth divides transmitted data into packets, and transmits each packet on one of 79 designated Bluetooth channels. Each channel has a bandwidth of 1   MHz. It usually performs 1600   hops per second, with adaptive frequency-hopping (AFH) enabled. Bluetooth Low Energy uses 2   MHz spacing, which accommodates 40 channels. Originally, Gaussian frequency-shift keying (GFSK) modulation was the only modulation scheme available. Since the introduction of Bluetooth 2.0+EDR, π/4-DQPSK (differential quadrature phase-shift keying) and 8-DPSK modulation may also be used between compatible devices. Devices fu
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