Bluetooth is a wireless technology that allows computers, telephones, personal data assistants (PDAs), and even home devices such as stereos and TVs to communicate with one another. Each Bluetooth device has a microchip embedded in it that can send and receive radio signals. It can send both data and voice. The radio signals are sent and received in the 2.4GHz radio band, often referred to as the industrial, scientific, and medical (ISM) band. Inside the chip is software called a link controller that does the actual work of identifying other Bluetooth devices and sending and receiving data.