VoiceXML Development Frequently Asked Questions

This FAQ contains answers to questions about VoiceXML development.

  1. Does Tellme support HTTP cookies?
  2. Which scripting languages can be used within VoiceXML applications?
  3. Which server-side scripting languages does Tellme support?
  4. Does Tellme support "special characters" in VoiceXML?
  5. Which audio formats does Tellme support?
  6. Does the Tellme voice browser transmit an HTTP user agent string?
  7. Does Tellme support Real Audio file formats?
  8. I'd like to restart my VoiceXML application without having to re-enter my developer ID and PIN.
  9. The on-line documentation is great, but are there any books available on VoiceXML 2.0?
Q: Does Tellme support HTTP cookies?
A: Yes. The Tellme platform accepts from and sends cookies to any Web server. See Using Cookies for more details.

Q: Which scripting languages can be used within VoiceXML applications?
A: The VoiceXML 1.0 Specification requires VoiceXML interpreters to support JavaScript (ECMAScript) within VoiceXML applications. The Tellme VoiceXML interpreter supports Javascript 1.5.

Q: Which server-side scripting languages does Tellme support?
A: Since the Tellme VoiceXML interpreter is a client browser and that browser fetches content across the Web from an HTTP server, application developers are free to implement their voice applications using any server-side framework supported by the Web server hosting the content. Example server-side frameworks include: CGIs written in Perl, C/C++, or Java; Active Server Pages written in VBScript or JavaScript, and servlets written in Java. The key is that these frameworks must be programmed to generate VoiceXML and transmit it to the VoiceXML interpreter.

Q: Does Tellme support "special characters" in VoiceXML?
A: Currently, the Tellme VoiceXML interpreter provides limited support for double-byte character encodings in VoiceXML documents. By default, the Tellme interpreter assumes that VoiceXML documents are encoded in UTF-8, which covers the normal set of ASCII characters (and more). Additional the Tellme interpreter supports the ISO 8859-1 encoding, widely used for European character sets. To specify this encoding, insert the following as the first line of any VoiceXML document:
<?xml version="1.0" encoding="iso-8859-1"?> Tellme has built-in support for the following encodings:
  • UTF-8
  • UTF-1
  • ISO-8859-1
  • us-ascii

Q: Which audio formats does Tellme support?
A: For now, the only supported audio format is ".wav". For optimal playback efficiency over the phone, save .wav files in 8KHz, 8-bit mu-law (G.711), mono format. Although the Tellme platform supports higher fidelity .wav formats (up to 44.1 KHz, 16-bit, stereo), current phones can only play back at 8KHz mu-law. We plan to support other formats in the future.

Q: Does the Tellme voice browser transmit an HTTP user agent string?
A: Yes. Tellme's user agent string is "Tellme/1.0 (I; en-US)".

Q: Does Tellme support Real Audio file formats?
A: For now Tellme only supports ".wav" files. However, there are nifty tools available that convert Real Audio to .wav files. Examples of such utilities include Streambox Ripper by Streambox.com , and Total Recorder from High Criteria .

Q: I'd like to restart my VoiceXML application without having to re-enter my developer ID and PIN.
A: Just hit ** (star star) or say "Tellme Menu", and your application will be restarted immediately.

Q: The on-line documentation is great, but are there any books available on VoiceXML 2.0?
A: Check out VoiceXML: Professional Developers Guide by Chetan Sharma and Jeff Kunins.

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