In a multi-zone audio system distributed in multiple locations around a home or building, a keypad allows a person to control the volume and other aspects of audio being sent to a specific zone in which the keypad is located. Keypads are also used for security systems, etc. but for audio purposes refer to the audio controls found in multi-zone audio systems. eypads control volume in the room as well as selecting sources components (such as CD players or tuners) and controlling those components (such as playing a CD or changing a radio station). Keypads may be simple or complex containing a wide array of buttons or simply a volume control and source selector (a simple volume control is not a full-fledged keypad since all it does is adjust the volume level in a room). Some keypads have IR (infrared) sensors to allow remote control of functions without moving to the keypad itself. Keypads are a vital part of a multi-zone audio system allowing control that is necessary for such a system to operate.