Calls and inquiries can be made as voice input or via keyboard input and are automatically evaluated and answered by the IVR system. The answers can be given as voice output, via fax, short message, e-mail or callback.
IVR systems can be used as conversational speech systems to relieve routine tasks and for queue management in call centers and customer interaction centers( CIC). To enable IVR systems to perform database queries, they are also used as electronic directory assistance systems. As far as the control of IVR systems is concerned, this can be done via the subscriber's dial keypad or via voice inputs processed with speech recognition. In the case of the dial keypad, the two-tone method is used for the response. The automatic voice response is based on several prerecorded announcements that are activated via the keypad dialing. The caller's data shown by the phone display is stored in the IVR system. In the context of Unified Messaging Service( UMS), the implementation of a voice-guided menu, a Voice User Interface(VUI), is a good idea. The voice output is done via voice output systems, as e-mail, SMS, fax or by calling back an employee.