VoiceXML 2.1 Development Guide

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w3c Properties

The available VoiceXML browsers offer support for most, but not all, of the properties listed in the w3c 2.0 specification. The complete list of supported properties is detailed below:

Property	Value
audiofetchhint	`safe\|prefetch`

Details: The audiofetchhint property designates when audio content should be fetched from the server. When set to 'safe', (default), then the audio is only fetched when needed. When set to 'prefetch', then the platform will attempt to pre-load the audio files to optimize performance.

Property	Value
audiomaxage	`CDATA (86400\|one day default value)`

Details: The 'audiomaxage' property informs the platform exactly how long, in seconds, the maximum acceptable date range is to cache audio content. Note that cache control is always handled best by server-defined settings.

Property	Value
audiomaxstale	`CDATA (3600\|one hour default value)`

Details: The 'audiomaxstale' property defines how long, in seconds, that the maximum acceptable staleness of audio content should be. Note that cache control is always handled best by server-defined settings.

Property	Value
bargein	`true\|false`

Details: The 'bargein' property controls whether or not the TTS or audio prompts may be interrupted by a caller's voice input. This property defaults to 'true', unless specified.

Property	Value
bargeintype	`speech\|hotword`

Details: This property allows the developer to define which type of bargein, (via speech, DTMF or 'hotword' input), is to be considered a valid method of input to the application.

Property	Value
completetimeout	`CDATA`

Details: The 'completetimeout' property specifies the length of time after a user utterance where the interpreter will consider the utterance complete. Changing the default value of '.25s' upwards offers more reliability in catching a user's complete utterance, at the cost of sacrificing response time. This property will only be active when set to a lesser value than the incompletetimeout property.

Property	Value
confidencelevel	`CDATA`

Details: The 'confidencelevel' property allows you to adjust how accurate a user's utterance needs to be to get a valid grammar match. If one were to change the default value of '.45' to '0.1', then any utterance would be matched, while if it were to be adjusted to '1.0', then virtually every user utterance would be considered a 'nomatch'.

Property	Value
documentfetchhint	`prefetch\|safe`

Details: This property setting defines the behavior for document fetching within the application. When set to 'safe' , (default), then documents will be fetched as-needed. When set to 'prefetch', then the content will be pre-fetched, (if possible) to speed up fetch times.

Property	Value
documentmaxage	`CDATA (0s default)`

Details: The 'documentmaxage' setting allows the developer to specify how long, in seconds, the maximum acceptable date range is to cache the document(s) in question. Note that cache control is always handled best by server-defined settings.

Property	Value
documentmaxstale	`CDATA (0s default)`

Details: The 'documentmaxstale' property defines how long, in seconds, that the maximum acceptable staleness of application content should be. Note that cache control is always handled best by server-defined settings.

Property	Value
fetchaudio	`CDATA`

Details: The 'fetchaudio' attribute specifies the URI of a .wav file to play to the caller in the event of an extended document fetch. Essentially, while the fetch is being made, it allows the developer to play some filler music to the caller rather than presenting only silence.

Property	Value
fetchaudiodelay	`CDATA (2s default)`

Details: This property setting designates how long to wait before playing the wav file specified in any 'fetchaudio' attributes/properies. In some cases, such as a comparatively short, (2-4s), document fetch, it is 'smoother' to present silence rather than 1 second of the fetchaudio 'filler'.

Property	Value
fetchaudiominimum	`CDATA (4s default)`

Details: This property defines the minimum amount of time that any fetchaudio content is allowed to play. Often used in conjunction with the 'fetchaudiodelay' setting to refine fetchaudio behavior on a Global scale.

Property	Value
fetchtimeout	`CDATA`

Details: The 'fetchtimeout' property allows the developer to specify how long the Voice Browser should attempt to fetch a document before throwing a fatal 'error.badfetch' event.

Property	Value
grammarfetchhint	`safe\|prefetch`

Details: This property specifies when external grammar files should be fetched. The value of 'prefetch', (default) means that grammars are fetched whenever the VoiceXML page itself loads, whereas a value of 'safe' will only fetch the grammar when it is called for.

Property	Value
grammarmaxage	`CDATA (0s default)`

Details: The 'grammarmaxage' setting allows the developer to specify how long, in seconds, the maximum acceptable date range is to cache the grammar(s) in question. Note that cache control is always handled best by server-defined settings.

Property	Value
grammarmaxstale	`CDATA (0s default)`

Details: The 'grammarmaxstale' property defines how long, in seconds, that the maximum acceptable staleness of grammar should be. Note that cache control is always handled best by server-defined settings.

Property	Value
incompletetimeout	`CDATA`

Details: The 'incompletetimeout' property allows you to change the setting of when, after a caller pauses in mid-utterance, the interpreter will start to process said utterance. After the period of time specified, (2s default), the interpreter will process the utterance and return either a valid grammar match, or a 'nomatch' condition.

Property	Value
inputmodes	`dtmf\|voice`

Details: This property allows the developer to specify what types of input ()voice or dtmf) are allowable within the application. When set to 'dtmf' the application will ignore all voice input, and vice-versa.

Property	Value
interdigittimeout	`CDATA`

Details: This property specifies the amount of time between multiple dtmf inputs that a caller is allowed before the interpreter decides that the caller has finished. To tune any appreciable delay between dtmf input and the recognition return, the default value of '4s' can be adjusted downward to a more comfortable value, although at the expense of possibly truncating the caller's full dtmf input.

Property	Value
maxnbest	`CDATA`

Details: This property specifies the maximum number of interpretations that should be returned from the recognition when NBest post-processing is performed in the application. The default value for this property is '1'.

Property	Value
maxspeechtimeout	`CDATA`

Details: This setting defines the maximum duration of a user's speech that is to be accepted before throwing a 'maxspeechtimeout' event.

Property	Value
scriptfetchhint	`safe\|prefetch`

Details: This property specifies when external script files should be fetched. The value of 'prefetch', (default) means that scripts are fetched whenever the VoiceXML page itself loads, whereas a value of 'safe' will only fetch the grammar when it is called for.

Property	Value
scriptmaxage	`CDATA (0s default)`

Details: The 'scriptmaxage' setting allows the developer to specify how long, in seconds, the maximum acceptable date range is to cache the script(s) in question. Note that cache control is always handled best by server-defined settings.

Property	Value
sensitivity	`CDATA`

Details: The 'sensitivity' property allows you to adjust how sensitive the interpreter is to loud versus quiet input. Adjusting the default value of '0.5' upwards will make the interpeter more sensitive to quiet input, while adjusting this value downwards will make it less sensitive to quiet input. This property can be useful if your end user will be accessing the application in a very noisy environment, although it is advised that you use this property very carefully, as it may have a detrimental effect on recognition accuracy.

Property	Value
speedvsaccuracy	`CDATA`

Details: The 'speedvsaccuracy' property allows you to tune the trade off between utterance matching accuracy, and the speed of the return. If the default value of '0.5' is adjusted upwards, accuracy increases, but the speed of the return is hampered. Adjusting the value downwards will return results faster, at the expense of accuracy. Use this property with extraordinary caution, as this can negatively impact your application if used carelessly.

Property	Value
termchar	`(any dtmf key)`

Details: The property 'termchar' allows you to set the default dtmf key that signals the interpreter that dtmf entry is complete. This value, unless specified, defaults to the pound key '#'.

Property	Value
termtimeout	`CDATA`

Details: The 'termtimeout' property specifies the terminating timeout to use when recognizing DTMF input.

Property	Value
timeout	`CDATA`

Details: The 'timeout' property allows to to specify how long the interpreter will wait for a user utterance before it will throw a 'noinput' event. This property defaults to '5s', unless explicitly specified.

Property	Value
universals	`all\|none\|help\|cancel\|exit\|repeat`

Details:This property allows you to disable or enable the universal grammars for your application. By default, the value for this property is set to 'none'. See the section on universal grammars for further details.

ANNOTATIONS: EXISTING POSTS

awirtz

11/29/2004 3:10 PM (EST)

The values assigned to these properties should not be enclosed in single quotes like values assigned using the assign tag. (since this is a literal CDATA value, not a JavaScript expression)

Also note that when specifying a duration in seconds, the "s" is indeed part of the literal CDATA value.

Example:
<property name="incompletetimeout" value="4s"/>

safarishane

2/9/2006 12:12 PM (EST)

Is the W3C property for recording utterances during asr reco supported?

<property name="recordutterance" value="true"/>

http://www.w3.org/TR/voicexml21/#sec-reco_reco

Thanks,
Shane

steve.sax

2/9/2006 12:40 PM (EST)

Hello Shane,

At present, this 2.1-specific property is not enabled on out VoiceXML platform, but we do have plans for enabling this on our Prophecy platform in the very near future.

However, you can achive the very same functionality at present by employing the <voxeo:recordcall> extension element. Check the 'elements' section in the left-hand navigation pane to learn more about this element, and it's usage.

Warm Regards,

~Steve Sax

safarishane

2/9/2006 12:54 PM (EST)

Actually, I'm looking to only record the <nomatch> portions of a call. Please let me know when Prophesy is available in your hosted environment.

Thanks

steve.sax

2/9/2006 12:56 PM (EST)

hello Sahne,

Prophecy is available in the hosted environment already, but we don't yet support the property that you mentioned. bear in mind that Prophecy is still a Beta offering, so we can expect changes and updates daily.

~Steve

beta

8/23/2006 6:14 AM (EDT)

Isn't it included with Prophecy 7 now?

MattHenry

8/23/2006 1:02 PM (EDT)

Hi there,

Getting shadow variable results in the context of a nomatch event is a feature that we have not yet deployed to either voice center offering. This particular feature will require some sizable engineering effort to complete, and while this feature is on our to-do list, we do not yet have a date of deployment finalized.

When this is enabled, we will be sure to post details in our release notes, available in the Prophecy forums.

~Matthew henry

esirkin

10/11/2006 3:54 AM (EDT)

<property name="bargeintype" value="dtmf"/>

is not permitted according to the W3C spec. The spec says that only "hotword" and "speech" are to be used. The spec then goes on to say that using "speech" enables "dtmf", one should set

<property name="inputmodes" value="dtmf"/>

to restrict inputs to dtmf tones.

If this is something specific to Voxeo platform, then it is a nice feature but shouldn't it be documented as such?

eric

MattHenry

10/11/2006 11:27 AM (EDT)

Hi Eric,

This is a case of documentation meant for our older VXML platform, (Nuance VWS 2.0), seeping into our docset for the Voicecenter 5.5/7.0 documentation. Note that this property setting has no effect on the contemporary platforms we offer; the setting will just be ignored.

All the same, I'll see about getting this corrected in the docs so that this doesn't confuse anyone.

~Matthew henry

fliptone

8/5/2007 3:09 PM (EDT)

above you say "Note that cache control is always handled best by server-defined settings". Where are these settings defined?

VoxeoBrian

8/5/2007 3:19 PM (EDT)

Hello,

What is meant by setting cache control on the server side is specific to the web server you are using locally to server up content.

Here is an excellent link that outlines setting HTTP cache control headers, as well you should be able to find documentation specific to your server program, ie, Apache, IIS, etc.

http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html

Hope this helps!

Regards

Brian

H: Property Guide

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