Health concerns




Bluetooth uses the radio frequency spectrum in the 2.402 GHz to 2.480 GHz range, which is non-ionizing radiation, of similar bandwidth to the one used by wireless and mobile phones. No specific demonstration of harm has been demonstrated up to date, even if wireless transmission has been included by IARC in the possible carcinogen list. Maximum power output from a Bluetooth radio is 100 mW for class 1, 2.5 mW for class 2, and 1 mW for class 3 devices. Even the maximum power output of class 1 is a lower level than the lowest-powered mobile phones. UMTS and W-CDMA output 250 mW, GSM1800/1900 outputs 1000 mW, and GSM850/900 outputs 2000 mW.

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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

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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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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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