| A VoiceXML application consists of several | | | | TTS, audio play and record functions, as well as a |
| components, as shown in Figure 1: | | | | telephone network interface. |
| Application Server: Typically a Web server, which | | | | Internet-style network: A TCP/IP-based packet |
| runs the application logic, and may contain a | | | | network that connects the application server and |
| database or interfaces to an external database or | | | | telephony server via HTTP. |
| transaction server. | | | | Telephone Network: Typically the Public Switched |
| VoiceXML Telephony Server: A platform that runs | | | | Telephone Network (PSTN), but could be a |
| a VoiceXML interpreter that acts as a client to | | | | private telephone network (e.g. PBX), or VoIP |
| the application server. The interpreter understands | | | | packet network. Caller: Any telephone that can |
| VoiceXML dialogs and controls speech and | | | | connect to the telephone network. |
| telephony resources. These resource include ASR, | | | | |