In telephony, Interactive Voice Response, or IVR, is a phone technology that allows a computer to detect voice and touch tones using a normal phone call. The IVR system can respond with pre-recorded or dynamically generated audio to further direct callers on how to proceed. IVR systems can be used to control almost any function where the interface can be broken down into a series of simple menu choices. Once constructed IVR systems generally scale well to handle large call volumes. An evolution of IVR is the Interactive Voice & Video Response, or IVVR that allow automatic video contents and videocalling.

Def. Wikipedia @ http://en.wikipedia.org/wiki/Interactive_voice_response