BladeWareVXML Open-Source Interpreter

BladeWareVXML is an open-source VoiceXML interpreter that follows the W3C VoiceXML 2.0 dialog markup language specification, enabling developers to take advantage of well-known Web technologies and tools when building voice applications. An interpreter, like BladeWareVXML, is the keystone component of any standards-compliant voice browser.

BladeWareVXML is based on OpenVXi, originally developed at Carnegie Mellon University, and later supported by SpeechWorks International, Inc., and has been adopted by more telephony platforms than any VoiceXML interpreter. BladeWareVXML was specifically designed to integrate into an existing telephony platform. It consists of a collection of replaceable components to provide maximum flexibility to developers. Developers can keep the components they need and substitute their own where appropriate. BladeWareVXML is also easily enhanced to support proprietary grammar formats, URI types, and VoiceXML objects.

BladeWareVXML provides the VoiceXML component to all developers, who need to add VoiceXML capabilities to their products, eliminating the need to develop the technology on their own and to track changes and additions to the VoiceXML standard. For companies with VoiceXML platforms, BladeWareVXML serves as a reference to ensure that they are executing VoiceXML consistently so they can deliver cross-platform compatibility. As with other open-source technologies, developers can take advantage of any subsequent contributions to BladeWareVXML by Commetrex or any other developers worldwide.

BladeWareVXML is designed for portability. It is suitable for use in VoiceXML-based applications such as browsers, testers, and debuggers on a wide variety of architectures. Though workable for desktop systems, it targets high-density telephony systems.

BladeWareVXML is fully internationalized and language agnostic. Since it is based on OpenVXi, it has been used in dozens of languages including US English, Mexican Spanish, Japanese, French, German, and Korean.

Please be aware that BladeWareVXML, like its’ predecessor OpenVXi, is no longer an active project. However, BladeWareVXi, Commetrex’ commercial version of BladeWareVXML, is a very active project, with several new releases in the past year.

BladeWareVXML is not a VoiceXML browser. BladeWareVXi Browser is scheduled for release in 1Q2011. Integrating a stand-alone interpreter into a telephony platform requires engineering, testing and ongoing maintenance. A functional browser capable of processing user input and output requires the interpreter to be integrated with speech recognition, text-to-speech and telephony components, as well as subsystems for prompt playing and audio delivery. Integrators may want to replace or enhance the BladeWareVXML logging component to redirect messages to the platform’s management components. Also note that BladeWareVXML does not include tools for building VoiceXML applications. It does, however, work with any third party offering that outputs VoiceXML. For example, BladeWareStudio is a VoiceXML application tool available from Commetrex. Finally, BladeWareVXML is intended for deployments and does not include support for runtime debugging, at this time.


  • VoiceXML 2.1 compliant
  • DTMF recognizer
  • Supports all OpenVXi interfaces
  • Enhanced MRCP integration capability
  • SRGS grammar parser with SISR support
  • Full reference implementation
  • Significant performance improvements over OpenVXi


  • Meets latest industry standard
  • Easy to build DTMF applications
  • Easy to upgrade for OpenVXi-based platforms
  • Will reduce effort to integrate ASR/TTS
  • Meets latest industry standard for conformance testing
  • Higher-density systems

BladeWareVXi Browser Rollout

The initial release of BladeWareVXi Browser will include the following further enhancements:

  • Integration with Commetrex’ OTF Kernel/BladeWare
  • Extend the implementation of the DTMF recognizer to utilize OTF/BladeWare Signal Detector
  • Build INET OTF resource
  • Integrate the BladeWareVXML Interpreter with INET OTF resource
  • Determine the appropriate MRCP solution
  • Integrate MRCP solution

BladeWareVXML Interpreter Package Contents

BladeWareVXML Interpreter package consists of the following components:

  • VoiceXML interpreter source
  • BladeWareVXML interface headers
  • Reference implementations for the Internet, ECMAScript, Object, Log, Thread, and Value components
  • Reference simulator implementations for the Recognition, Prompt, and Telephony components
  • Reference application manager
  • HTML based Documentation
  • Sample VoiceXML applications
  • Microsoft Visual C++ 8.0 Project files to build the source on Win32
  • GNU make makefiles to build the source on Linux
  • Pre-built binaries for Win32

The architecture of the overall system is described in the OpenVXi Architecture Description, while BladeWareVXML interfaces are similar to the OpenVXi Interface Reference. The OpenVXi Release Notes describe the VoiceXML 2.1 interpretation and coverage as well as limitations of the reference component implementations. The Commetrex Public License provides licensing terms.

Licensing Options

BladeWareVXML is available for free download from It should be noted that development efforts ceased on BladeWareVXML in 2008 and it is no longer an active project with Commetrex. All current and future development is happening with the commercial version, BladeWareVXi. The open-source interpreter is still available, however, under the GNU General Public License (GPL) at For developers who wish to use BladeWareVXML for commercial distribution without GPL restrictions, and with the latest enhancements, Commetrex offers a commercial product, BladeWareVXi, the license which includes source code, as well as software support and maintenance. Additional advantages of the commercial license include redistribution rights, warranty indemnification, access to beta versions, and priority response to feature requests.

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