Bluetooth uses the license-free frequency range from 2.402 to 2.480 GHz for wireless communication. This frequency range is also referred to as the ISM band. It has been designated for license-free use worldwide, but is subject to interference from other technologies. WiFi networks, cordless phones or microwave ovens can influence the Bluetooth signal quality.
Bluetooth is divided into three classes, according to the maximum transmission power. Class one reaches ranges of up to 100 metres, at a maximum output power of 100 milliwatts, but at the other end of the scale, the typical operating range of class three Bluetooth is one metre, with a transmission strength of one milliwatt.