VGAPI Overview
Introduction
Cisco Tcl and VoiceXML applications on the Cisco gateway provide Interactive Voice Response (IVR) features and call control functionality such as call forwarding, conference calling, and voice mail.
IVR systems provide information through the telephone in response to user input in the form of spoken words or dual tone multi frequency (DTMF) signaling. The Cisco voice gateway allows an IVR application to be used during call processing. A Cisco voice gateway can have several IVR applications to accommodate many different services, and you can customize the IVR applications to present different interfaces to various callers.
Benefits
- Adds scalability to the IVR infrastructure
- Enables service providers to offer an enhanced unified communications service, in which a subscriber uses the same number for both voice and fax messages. The flexibility of the application allows personalized services to be configured for different customers or for different called numbers.
- Supports all standard telephony signaling: H.323, Media Gateway Control Protocol (MGCP), and Session Initiation Protocol (SIP).
- Allows larger prompts to be played
- Allows use of an external audio server
- Enables integration between Tcl and VoiceXML and the development of hybrid applications
- Provides TTS and ASR support through VoiceXML and a distributed server farm
- Implements AAA authentication and authorization.
Tech Details
Cisco gateway voice applications can be developed using one or both of these two scripting languages:
- Tcl IVR 2.0 Tcl-based scripting with a proprietary Cisco API. Provides extensive call control capabilities, signaling, and GTD manipulation.
- VoiceXML Standards-based markup language for voice browsers. Existing web server and application logic can be used for VoiceXML applications, requiring less time and money to build infrastructure and perform development than traditional proprietary IVR systems require.
- Applications can also be developed using a hybrid of both Tcl IVR and VoiceXML.
Voice Gateway API Architecture
Below is a sample diagram that illustrates the interaction between a caller and a VoiceXML auto attendant (AA) application. The application prompts to collect account number and uses this to access the customer records. The web application can then prompt the caller through checking balances, transferring funds, or other self-help activities, or it can transfer the caller to an agent for personalized service.