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Voice Application Development

Cisco IOS VoiceXML Technology

Q & A

Cisco IOS VoiceXML Technology

Q. What is Cisco IOS® VoiceXML?

A. Voice eXtensible Markup Language, or VoiceXML, is a language similar to HTML that brings the full power of Web development and content delivery to interactive-voice-response (IVR) applications.

VoiceXML is designed for creating audio dialogs that feature synthesized speech, digitized audio, recognition of spoken and dual tone multifrequency (DTMF) key input and recording of spoken input. It is a common language for content providers, tool providers, and platform providers and promotes service portability across implementation platforms. VoiceXML separates user interaction presentation logic in VoiceXML "voice Web pages" from service logic and shields application authors from low-level, platform-specific IVR and call control details. It is easy to use for simple interactions, yet it provides language features to support complex IVR dialogs.

Q. On what platforms is Cisco IOS VoiceXML available?

A. Cisco IOS VoiceXML is available on Cisco AS5000 Series universal gateways and the Cisco 3600 Series of multiservice routers. The Cisco AS5300, Cisco AS5350, Cisco AS5400, Cisco 3640, and Cisco 3660 models are supported, running Cisco IOS Software Release 12.2(11)T or later.

Other Cisco IOS platforms are under consideration for support in future Cisco IOS Software releases. VoiceXML support is also available as part of the Cisco IP IVR Version 3.0 product line for Cisco Call Manager networks.

On Cisco AS5350 and Cisco AS5400 platforms, the optional Ultra Port or Enhanced Voice software license is required.

Q. What version of the VoiceXML standard is supported?

A. Cisco IOS VoiceXML is based on the first public World Wide Web Consortium (W3C) Working Draft of VoiceXML 2.0 published October 23, 2001. The draft specification is available at:


Q. Which Automated Speech Recognition (ASR) and text-to-speech (TTS) engines are supported?

A. Cisco IOS VoiceXML interfaces with ASR and TTS media servers from Nuance (www.nuance.com) and Speechworks (www.speechworks.com).

The interface to the media servers uses openly specified Media Resource Control Protocol (MRCP) extensions of the IETF Real-Time Streaming Protocol (RFC 2326):


A standard, based on MRCP, is being developed in the IETF SPEECHSC Working Group:


Q. Does Cisco IOS VoiceXML include ASR and TTS licenses and server hardware?

A. No. ASR and TTS software is available for purchase directly from Cisco partners Nuance and SpeechWorks for Linux, Solaris, or Windows servers.

Q. What telephony interfaces are supported?

A. All line-card interfaces and signaling protocols available on the Cisco IOS gateways are supported, including T1/E1 ISDN Primary Rate Interface (PRI), channel associated signaling (CAS), Signaling System 7 (SS7) ISDN User Part (ISUP), H.323, Session Initiation Protocol (SIP), Media Gateway Control Protocol (MGCP), and others.

Q. What enhanced services and voice applications are available with Cisco IOS VoiceXML?

A. Cisco IOS VoiceXML provides a platform to execute voice applications but does not include specific applications.

Enterprises and service providers are using VoiceXML to deliver a variety of Web-based IVR applications. For instance, B2.com is using VoiceXML on Cisco AS5350 universal gateways for subscriber self-provisioning of residential voice-over-IP (VoIP) services.

The Cisco Internet Service Node is using the Cisco IOS VoiceXML platform for Web-based, IVR services for both IP and traditional telephony networks. Visit:


VoiceXML applications are also available from Cisco partners, such as voice and unified messaging solutions from Openwave. See:


Q. What tools can I use to develop VoiceXML applications?

A. Any Web server site-creation tools can be used to create VoiceXML applications, such as IBM WebSphere, Perl, PHP Hypertext Preprocessor (PHP), Java Server Page (JSP), Active Server Pages (ASP), ColdFusion, or other technologies.

Q. What languages are supported for ASR and TTS?

A. Many European and Asian languages and local variants are supported by Cisco partners Nuance and Speechworks. For a specific list of supported languages, contact Nuance and Speechworks directly at www.nuance.com and www.speechworks.com.

Q. Are any ASR grammar or subdialog libraries available to help build VoiceXML applications?

A. Grammar and subdialog libraries are not included as part of Cisco IOS VoiceXML. Libraries are available from Nuance, Speechworks, and other third parties.

Q. Where can I get more information about VoiceXML?

A. Cisco IOS VoiceXML technology and feature documentation are available on Cisco.com at:



The Cisco Developer Support Program provides technical assistance and professional services:


The W3C Voice Browser Working Group is drafting the VoiceXML 2.0 standard, and the VoiceXML Forum is an industry group promoting the language. Both are good sources of information about the specifications, tools, VoiceXML applications, and related events. Visit:



Several books about VoiceXML are available, including VoiceXML: Professional Developer's Guide by Chetan Sharma and Jeff Kunins, John Wiley & Sons, ISBN: 0471418935.

Q. Who do I contact for more information about Cisco IOS VoiceXML and for product-enhancement requests?

A. Contact your account team or send e-mail to:


Q. Is speech verification supported by voiceXML?

A. No, ability to authenticate callers using speech verification is not yet available in IOS VoiceXML.

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