When building mobile and wireless applications, most corporations do not give adequate consideration to the benefits that a voice interface provides. Voice applications make it possible to extend enterprise data to anyone with a telephone, wireless or otherwise. Unlike the proprietary, inflexible systems of the past, the new wave of voice applications provides an open, robust solution for a variety of business and consumer applications.
This chapter discusses building voice applications using the Voice eXtensible Markup Language, VoiceXML. Unlike other applications described in this book, VoiceXML provides a voice, rather than visual, interface to enterprise systems. The VoiceXML architecture is very similar to that of Internet applications, with the Web browser replaced by a voice browser, and the handheld device replaced with a telephone. Voice interfaces give true universal access to your applications.
After reviewing the history of VoiceXML, we will examine the VoiceXML architecture and then provide information on building VoiceXML applications. The goal is to give you enough information so that you can make educated decisions as to whether a voice interface is suitable for your enterprise applications. An overview of the VoiceXML language is also given, to enable you to get started building custom solutions.
Most of this chapter is based on the working draft of the VoiceXML 2.0 specification released by the W3C. The code samples have been developed and tested with TellMe Studio, a leading VoiceXML platform.