Last reviewed: 3/23/2024 12:33:45 PM

<property>

A <property> element controls implementation platform settings.

Syntax

<property name="string" 
          value="string" />

Attributes

name

The name of the property.

Generic Speech Recognizer Property Description
confidencelevel The speech recognition confidence level, a float value in the range of 0.0 to 1.0. Results are rejected (a nomatch event is thrown) when application.lastresult$.confidence is below this threshold. A value of 0.0 means minimum confidence is needed for a recognition, and a value of 1.0 requires maximum confidence. The value is a Real Number Designation. The default value is 0.5.
sensitivity Set the sensitivity level. A value of 1.0 means that it is highly sensitive to quiet input. A value of 0.0 means it is least sensitive to noise. The value is a Real Number Designation. The default value is 0.5.
speedvsaccuracy A hint specifying the desired balance between speed vs. accuracy. A value of 0.0 means fastest recognition. A value of 1.0 means best accuracy. The value is a Real Number Designation. The default is value 0.5.
completetimeout The length of silence required following user speech before the speech recognizer finalizes a result (either accepting it or throwing a nomatch event). The complete timeout is used when the speech is a complete match of an active grammar. By contrast, the incomplete timeout is used when the speech is an incomplete match to an active grammar.<br /><br /> A long complete timeout value delays the result completion and therefore makes the computer's response slow. A short complete timeout may lead to an utterance being broken up inappropriately. Reasonable complete timeout values are typically in the range of 0.3 seconds to 1.0 seconds. The value is a Time Designation. The default is platform-dependent.<br /><br /> Although platforms must parse the completetimeout property, platforms are not required to support the behavior of completetimeout. Platforms choosing not to support the behavior of completetimeout must so document and adjust the behavior of the incompletetimeout property as described below.
incompletetimeout The required length of silence following user speech after which a recognizer finalizes a result. The incomplete timeout applies when the speech prior to the silence is an incomplete match of all active grammars. In this case, once the timeout is triggered, the partial result is rejected with a nomatch event.<br /><br /> The incomplete timeout also applies when the speech prior to the silence is a complete match of an active grammar, but where it is possible to speak further and still match the grammar. By contrast, the complete timeout is used when the speech is a complete match to an active grammar and no further words can be spoken.<br /><br /> A long incomplete timeout value delays the result completion and therefore makes the computer's response slow. A short incomplete timeout may lead to an utterance being broken up inappropriately.<br /><br /> The incomplete timeout is usually longer than the complete timeout to allow users to pause mid-utterance (for example, to breathe).<br /><br /> Platforms choosing not to support the completetimeout property (described above) must use the maximum of the completetimeout and incompletetimeout values as the value for the incompletetimeout.<br /><br /> The value is a Time Designation.
maxspeechtimeout The maximum duration of user speech. If this time elapsed before the user stops speaking, the event "maxspeechtimeout" is thrown. The value is a Time Designation. The default duration is platform-dependent.
Generic DTMF Recognizer Properties Description
interdigittimeout The inter-digit timeout value to use when recognizing DTMF input. The value is a Time Designation. The default is platform-dependent.
termtimeout The terminating timeout to use when recognizing DTMF input. The value is a Time Designation. The default value is 0s.
termchar The terminating DTMF character for DTMF input recognition. The default value is #.
Fetch Prompt and Collect Properties Description
bargein The bargein attribute to use for prompts. Setting this to true allows bargein by default. Setting it to false disallows bargein. The default value is true.
bargeintype Sets the type of bargein to be speech or hotword. Default is platform-specific.
timeout The time after which a noinput event is thrown by the platform. The value is a Time Designation. The default value is platform-dependent.
Fetching Properties Description
audiofetchhint This tells the platform whether or not it can attempt to optimize dialog interpretation by pre-fetching audio. The value is either safe to say that audio is only fetched when it is needed, never before; or prefetch to permit, but not require the platform to pre-fetch the audio. The default value is prefetch.
audiomaxage Tells the platform the maximum acceptable age, in seconds, of cached audio resources. The default is platform-specific.
audiomaxstale Tells the platform the maximum acceptable staleness, in seconds, of expired cached audio resources. The default is platform-specific.
documentfetchhint Tells the platform whether or not documents may be pre-fetched. The value is either safe (the default), or prefetch.
documentmaxage Tells the platform the maximum acceptable age, in seconds, of cached documents. The default is platform-specific.
documentmaxstale Tells the platform the maximum acceptable staleness, in seconds, of expired cached documents. The default is platform-specific.
grammarfetchhint Tells the platform whether or not grammars may be pre-fetched. The value is either prefetch (the default), or safe.
grammarmaxage Tells the platform the maximum acceptable age, in seconds, of cached grammars. The default is platform-specific.
grammarmaxstale Tells the platform the maximum acceptable staleness, in seconds, of expired cached grammars. The default is platform-specific.
objectfetchhint Tells the platform whether the URI contents for <object> may be pre-fetched or not. The values are prefetch (the default), or safe.
objectmaxage Tells the platform the maximum acceptable age, in seconds, of cached objects. The default is platform-specific.
objectmaxstale Tells the platform the maximum acceptable staleness, in seconds, of expired cached objects. The default is platform-specific.
scriptfetchhint Tells whether scripts may be pre-fetched or not. The values are prefetch (the default), or safe.
scriptmaxage Tells the platform the maximum acceptable age, in seconds, of cached scripts. The default is platform-specific.
scriptmaxstale Tells the platform the maximum acceptable staleness, in seconds, of expired cached scripts. The default is platform-specific.
fetchaudio The URI of the audio to play while waiting for a document to be fetched. The default is not to play any audio during fetch delays. There are no fetchaudio properties for audio, grammars, objects, and scripts. The fetching of the audio clip is governed by the audiofetchhint, audiomaxage, audiomaxstale, and fetchtimeout properties in effect at the time of the fetch. The playing of the audio clip is governed by the fetchaudiodelay, and fetchaudiominimum properties in effect at the time of the fetch.
fetchaudiodelay The time interval to wait at the start of a fetch delay before playing the fetchaudio source. The value is a Time Designation. The default interval is platform-dependent, e.g. "2s". The idea is that when a fetch delay is short, it may be better to have a few seconds of silence instead of a bit of fetchaudio that is immediately cut off.
fetchaudiominimum The minimum time interval to play a fetchaudio source, once started, even if the fetch result arrives in the meantime. The value is a Time Designation. The default is platform-dependent, e.g., "5s". The idea is that once the user does begin to hear fetchaudio, it should not be stopped too quickly.
fetchtimeout The timeout for fetches. The value is a Time Designation. The default value is platform-dependent.
Miscellaneous Properties Description
inputmodes This property determines which input modality to use. The input modes to enable: dtmf and voice. On platforms that support both modes, inputmodes defaults to "dtmf voice". To disable speech recognition, set inputmodes to "dtmf". To disable DTMF, set it to "voice". One use for this would be to turn off speech recognition in noisy environments. Another would be to conserve speech recognition resources by turning them off where the input is always expected to be DTMF. This property does not control the activation of grammars. For instance, voice-only grammars may be active when the inputmode is restricted to DTMF. Those grammars would not be matched, however, because the voice input modality is not active.
universals Platforms may optionally provide platform-specific universal command grammars, such as "help", "cancel", or "exit" grammars, that are always active (except in the case of modal input items) and which generate specific events.<br /><br /> Production-grade applications often need to define their own universal command grammars, e.g., to increase application portability or to provide a distinctive interface. They specify new universal command grammars with <link> elements. They turn off the default grammars with this property. Default catch handlers are not affected by this property.<br /><br /> The value "none" is the default, and means that all platform default universal command grammars are disabled. The value "all" turns them all on. Individual grammars are enabled by listing their names separated by spaces; for example, "cancel exit help".
maxnbest This property controls the maximum size of the "application.lastresult$" array; the array is constrained to be no larger than the value specified by 'maxnbest'. This property has a minimum value of 1. The default value is 1.

value

he value of the property.

Children

none

Parents

<form>

Variables

none

Example

The following example illustrates using a property.

<form id="no_bargein_form"> 
  <property name="bargein" value="false"/> 
  <block> 
    <prompt>
      This introductory prompt cannot be barged into.
    </prompt> 
    <prompt>
      And neither can this prompt.
    </prompt> 
    <prompt bargein="true">
      But this one <emphasis>can</emphasis> be barged into.
    </prompt> 
  </block> 
  <field type="boolean">
    <prompt>
      Please say yes or no.
    </prompt>
  </field>  
</form>

Version Information

Supported in: VoiceXML 1.0, VoiceXML 2.0, and VoiceXML 2.1.