Bluetooth (Bluetooth) is an open global specification for wireless data and voice communications, which is based on a low-cost, close-range wireless connection for fixed and mobile devices to establish a communication environment for a special kind of close-range wireless technology connection. Bluetooth enables a number of portable mobile devices and computer equipment to connect to the Internet without cables and to access the Internet wirelessly.
The Bluetooth band is 2400_2483.5MHz (including guard bands). This is the short-range 2.4 GHz radio band of the worldwide unlicensed (but not unregulated) Industrial, Scientific and Medical (ISM) band. Bluetooth uses frequency hopping technology to split the transmitted data into packets and transmit the packets through each of the 79 designated Bluetooth channels. Each channel has a bandwidth of 1 MHz. Bluetooth 4.0 uses 2 MHz spacing and can accommodate 40 channels. The first channel starts at 2402 MHz, with one channel every 1 MHz up to 2480 MHz. with the AdaptiveFrequency-Hopping (AFH) feature, this is typically 1600 hops per second.