Bluetooth Band is 2400 – 2483.5MHz (including protective bands). This is the global range of industrial, scientific and Medical (ISM) bands of 2.4 GHz short-distance radio frequencies without licensing (but not unregulated).
Bluetooth uses FH technology to divide the transmitted data into packets and transmit packets separately via the specified Bluetooth channel in 79. Each channel has a bandwidth of 1 MHz. Bluetooth 4.0 uses a 2 MHz pitch to accommodate 40 channels. The first channel starts at 2402 MHz, one channel per 1 MHz, to 2480 MHz. With the appropriate frequency hopping (Adaptive Frequency-Hopping, abbreviated AFH) function, usually per second to skip the 1600 times.