Integration with Telephones, Speech Engines, and Other Technologies

Microsoft Telephony Application Programming Interface (TAPI) provides a well-documented set of application interfaces designed to handle telephone system integration. TAPI isolates an application from the complexities of the telephone system and lets developers focus on their programming goals. WTE supports the TAPI 3.0 interface to access telephony line devices used for IVR, such as voice boards and modems. WTE does not include a TAPI interface for accessing a switching device such as automatic call distributor (ACD), private branch exchange (PBX), or key system. However, WTE allows application writers to use any standard to access these switching devices.

Web telephony applications also use Microsoft Speech API (SAPI) technology, which performs speech recognition (SR) and text to speech (TTS) over any SAPI-compliant speech engine. If no other speech engine is selected, Web telephony uses the Microsoft automatic system reconfiguration (ASR) and TTS engines. Note that the Microsoft ASR engine must be installed from the SAPI 4.0a Software Developer's Kit (SDK)—it is not installed by default.

The Web provides a solid integration model for IVR-related technologies. Many of the technologies used in Web development apply to IVR as well, such as security and authentication, database access, and unified messaging. Because many vendors of such technologies provide ActiveX or Active Server scripting interfaces, their integration with HTML and Visual Basic scripts is routine. Web telephony provides access to the TAPI call object for scripts and ActiveX components designed to interact with the caller or affect the progress of a call.