Bluetooth is a short-range communications support device (usually within 10m) radio technology. Capable of wireless information exchange between including mobile phones, PDA, wireless headsets, laptops, peripherals and other related equipment. Bluetooth standard IEEE802.15, operate in the 2.4GHz frequency band, the bandwidth is 1Mb / s.

"Bluetooth" (Bluetooth) was originally a 10th century Danish king unity, he will unify the then Sweden, Finland and Denmark. Use his name to name this new technical standards, containing unify the fragmented situation mean. 

Bluetooth technology uses high-speed frequency hopping (FH, Frequency Hopping) and time division multiple access (TDMA, Time DivesionMuli-access) and other advanced technology, in close proximity to several of the most inexpensive digital devices (mobile devices, fixed communications equipment, computers and terminal equipment, a variety of digital data systems, such as digital cameras, digital video cameras, and even household appliances, automation equipment) reticular linked. Bluetooth technology is a network of various peripheral interface unification bridge, which eliminates wires between devices, and replaced with a wireless connection.

Bluetooth (Bluetooth) is a technical standard by Toshiba, Ericsson, IBM, Intel and Nokia in May 1998 jointly proposed short-range wireless digital communications. Its goal is to achieve maximum data transfer speed 1Mb / s (effective transmission speed of 721kb / s), the maximum transmission distance of 10 meters, the user does not have to go through an application can use the 2.4GHz ISM (industrial, scientific, medical) band, in its the establishment of 79 channel bandwidth of 1MHz, with 1600 times per second switching frequency, roller spread spectrum technology to achieve tooth way radio transceiver.

Advantages of Bluetooth technology: support for voice and data transmission; using radio technology, large transmission range, penetrate and spread among different substances substances; using frequency-hopping spread-spectrum technology, anti-jamming, easy to eavesdrop; do not use in various countries restricted spectrum, in theory, there is no interference problem; low power consumption; low cost. Bluetooth Disadvantages: slow transfer speed. 

Bluetooth technology performance parameters: the effective transmission distance of 10cm ~ 10m, increasing the transmit power up to 100 meters, and even farther. Transceiver operating frequency of 2.45GHz, coverage is separated by 1MHz of 79 channels (from 2.402GHz to 2.480GHz). Using short packet data transmission technology, frequency hopping spread spectrum technology, 1600 times / sec, to prevent eavesdropping and avoid interference; each transmission of a packet, packet size from 126 ~ 287bit; the contents of the packet may contain data or voice is different service information. Data transmission bandwidth for each direction of simultaneous connections can reach 32.6Kbps, close to 10 times the typical 56kb / s Modem analog connection speed, asynchronous connection allows a direction of data transfer rates up to 721kb / s, for uploading or downloading, which rate at which the opposite direction is 57.6kb / s; the data transmission channel is set aside three simultaneous synchronous voice channels, each bandwidth of 64kb / s; voice and data may be mixed in one channel, a 64kb / s simultaneous voice connectivity and an asynchronous data connection. Network connections using encryption technology, while using password authentication to connect devices, which can constitute a Bluetooth piconet (Piconet) and equipment within the other seven, a Bluetooth device can simultaneously join eight different micro-grid, each micro-network were 1Mb / s transfer bandwidth, when two or more devices to share a Channel, you can form a Bluetooth piconet, a unit led by the transmission quantity of them, when the device is not yet a Bluetooth piconet, it first goes into standby state.