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You can use the Gather XML element to collect user input through automatic speech recognition or DTMF “digit press” inputs. When collecting speech as input, Vobiz transcribes and relays a user’s speech to the specified action URL in real time. When collecting input through digit press, Vobiz relays the digits entered to the specified action URL. The Gather XML element supports simultaneous detection of both speech and digit press inputs.

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Nesting elements

You can nest Speak XML (text-to-speech) and Play XML elements inside Gather XML to prompt users for inputs. This is useful for building interactive voice response (IVR) experiences.

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Attributes

action (string, required) Callback-retry configurable The input is sent to a specific URL. See the “parameters sent to the action URL” table below for more information. Allowed values: a fully qualified URL method (string) The HTTP method to use when invoking the action URL. Allowed values: GET, POST Defaults to POST. inputType (string) The type of input(s) you expect to receive. Allowed values: dtmf, speech, dtmf speech When set to dtmf speech, Vobiz listens for both speech and digit inputs. The input that’s detected first is relayed to the action URL. executionTimeout (integer) Maximum execution time, in seconds, for which input detection is carried out. If the user fails to provide input within the timeout period, the next element in the response will be processed. This duration is counted after nested Play/Speak elements have ended. Allowed values: 5 to 60 Defaults to 15. digitEndTimeout (string) Time, in seconds, allowed between consecutive digit inputs. If no new digit input is provided within the digitEndTimeout period, digits entered until then will be processed. Allowed values: 2 to 10, or auto Defaults to auto. This attribute is applicable to input types dtmf and dtmf speech. speechEndTimeout (string) Time, in seconds, that Vobiz waits for more speech once silence is detected before it stops speech recognition. At that point, a transcription of the collected speech is relayed to the action URL. Allowed values: 2 to 10, or auto Defaults to auto. This attribute is applicable to input types speech and dtmf speech. finishOnKey (string) A digit that the user can press to submit digits. Allowed values: One and only one of 0–9, *, #, <empty string>, none Defaults to #. If set to <empty string> or none, input capture will end based on a timeout or the numDigits attribute. This attribute is applicable to input types dtmf and dtmf speech. numDigits (integer) The maximum number of digits to be processed in the current operation. Vobiz relays the digits to the action URL as soon as the maximum number of digits specified is collected. Allowed values: 1 to 32 Default: 32 This attribute is applicable to input types dtmf and dtmf speech. speechModel (string) The automatic speech recognition (ASR) model to use for transcribing the speech. Allowed values: default, command_and_search, phone_call Default: default This attribute is applicable to input types speech and dtmf speech.
  • command_and_search: Optimized for short queries such as voice commands and voice search.
    • phone_call: Optimized for transcribing audio from a phone call where the quality of the audio is slightly inconsistent.
    • telephony: telephony is an enhanced version of the phone_call model, optimized for audio typically originating from phone calls.
    • default: Optimized for audio that is not one of the specific audio models such as long-form audio.
hints (string) A list of phrases to act as “hints” to the speech recognition model; these phrases can boost the probability that such words or phrases will be recognized. Phrases may be provided both as small groups of words or as single words. Allowed values: a non-empty string of comma-separated phrases Limits:
  • Phrases per request: 500
    • Characters per request: 10,000
    • Characters per phrase: 100
This attribute is applicable to input types speech and dtmf speech. language (string) Specifies the language Vobiz should recognize from the user. Allowed values: See list of supported languages Defaults to en-US. This attribute is applicable to input types speech and dtmf speech. interimSpeechResultsCallback (string) Callback-retry configurable If interimSpeechResultsCallback URL is specified, requests to this URL are made in real-time as Vobiz recognizes speech. See the “parameters sent to the interimSpeechResultsCallback URL” table below for more information. Allowed values: a fully qualified URL This attribute is applicable to input types speech and dtmf speech. interimSpeechResultsCallbackMethod (string) The HTTP method to use when invoking the interimSpeechResultsCallback URL. Allowed values: GET, POST Defaults to POST. This attribute is applicable to input types speech and dtmf speech. log (boolean) If true, Vobiz will log digits or recognized speech from the caller. If false, logging will be disabled while processing the Gather element. Allowed values: true, false Defaults to true. redirect (boolean) If true, redirect to action URL. If false, only request the URL and continue to the next element. Allowed values: true, false Defaults to true. profanityFilter (boolean) If true, filters out profane words. Words filtered out are transcribed with their first letter and asterisks for the remaining characters (e.g. f***). The profanity filter operates on single words; it doesn’t detect abusive or offensive speech that’s a phrase or a combination of words. Allowed values: true, false Defaults to false. This attribute is applicable to input types speech and dtmf speech.

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Parameters sent to the action URL

In addition to the standard action URL request parameters, these parameters are sent to the action URL specified.
ParameterDescription
InputTypeThe type of input detected. Allowed values: dtmf, speech
DigitsThe digits entered by the caller, excluding the finishOnKey input, if used. Empty if inputType is speech.
SpeechThe transcribed result of the caller’s speech. Empty if inputType is dtmf.
SpeechConfidenceScoreA confidence score between 0.0 and 1.0. The higher the score, the more likely the transcription is accurate.
BilledAmountThe total amount billed for speech input transcription.

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Parameters sent to the interimSpeechResultsCallback URL

In addition to the standard callback URL request parameters, these parameters are sent to the interim speech results callback URL.
ParameterDescription
StableSpeechThe stable transcribed result of the user’s speech.
UnstableSpeechThe newer, unstable transcribed result of the user’s speech. This is an interim result and may change as more speech is gathered.
StabilityLikelihood that the recognizer will not change its guess about the interim result. Range: 0.0 (completely unstable) to 1.0 (completely stable). Only applies to unstable speech.
SequenceNumberSequence number of the interim speech callback, to help with ordering incoming callback requests.

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Examples

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Collect a single DTMF digit (IVR menu)

Nest a Speak or Play element to prompt the caller. With numDigits="1", Vobiz posts to the action URL as soon as one digit is pressed. 
<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Gather action="https://yourapp.com/menu-choice" method="POST"
            inputType="dtmf" numDigits="1" executionTimeout="10">
        <Speak>Press 1 for sales, 2 for support, or 0 for an operator.</Speak>
    </Gather>
    <Speak>We didn't receive your input. Goodbye.</Speak>
    <Hangup/>
</Response>

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Collect a multi-digit number with finishOnKey

For variable-length input such as an account number, set finishOnKey="#" and let the caller signal completion. 
<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Gather action="https://yourapp.com/account" method="POST"
            inputType="dtmf" numDigits="12" finishOnKey="#" executionTimeout="20">
        <Speak>Enter your account number, then press pound.</Speak>
    </Gather>
    <Redirect>https://yourapp.com/answer</Redirect>
</Response>

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Collect speech input

<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Gather action="https://yourapp.com/intent" method="POST"
            inputType="speech" language="en-US" speechEndTimeout="auto"
            hints="billing,support,sales">
        <Speak>In a few words, tell us what you're calling about.</Speak>
    </Gather>
    <Speak>Sorry, we didn't catch that.</Speak>
</Response>

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Accept either speech or digits

With inputType="dtmf speech", whichever input Vobiz detects first is the one relayed to the action URL. 
<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Gather action="https://yourapp.com/choice" method="POST"
            inputType="dtmf speech" numDigits="1" speechEndTimeout="auto">
        <Speak>Say "yes" or press 1 to confirm. Say "no" or press 2 to cancel.</Speak>
    </Gather>
</Response>

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Webhook payload sent to the action URL

After the caller responds (or input ends), Vobiz POSTs the standard call parameters plus the Gather-specific parameters to your action URL.
DTMF input
POST /menu-choice HTTP/1.1
Host: yourapp.com
Content-Type: application/x-www-form-urlencoded

CallUUID=xyz789&From=14155551234&To=14155559999&Direction=inbound&InputType=dtmf&Digits=1&Speech=
Speech input
POST /intent HTTP/1.1
Host: yourapp.com
Content-Type: application/x-www-form-urlencoded

CallUUID=xyz789&From=14155551234&To=14155559999&Direction=inbound&InputType=speech&Digits=&Speech=I+have+a+billing+question&SpeechConfidenceScore=0.92&BilledAmount=0.0050

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Edge cases and tips

  • No input / timeout. If the caller provides no input within executionTimeout seconds (counted after nested Play/Speak finishes), Vobiz moves on to the next element in the document. Always place fallback XML (a retry, a Redirect back to the menu, or a Hangup) after the Gather. By default, Vobiz still POSTs to the action URL with empty Digits and Speech on timeout - check for empty values in your handler.
  • Use executionTimeout, never timeout. Gather has no timeout attribute. The timeout attribute belongs only to Dial and Number. The valid range for executionTimeout is 5-60 seconds (default 15).
  • finishOnKey is excluded from Digits. The terminating key (default #) is not included in the Digits parameter. Set finishOnKey="" or finishOnKey="none" to rely solely on numDigits or the timeout.
  • numDigits ends collection early. Vobiz posts as soon as it collects numDigits digits, before the timeout or finishOnKey. For single-key menus, set numDigits="1" for the snappiest response.
  • DTMF vs speech. Use dtmf for menus and structured input (account numbers, PINs) - it is precise and free. Use speech for open-ended intent capture; it incurs a per-request charge (see Pricing for speech recognition) and returns a SpeechConfidenceScore you should threshold before acting. Combine with dtmf speech when you want to accept both.
  • Improve recognition. Pass domain words via hints, set the correct language (see supported languages), and pick a speechModel suited to the input (command_and_search for short commands, phone_call/telephony for call audio).
  • Validate input server-side. Never trust Digits or Speech directly in queries or business logic - sanitize and range-check them in your handler.