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Frequently asked questions about call recording, transcription, text-to-speech, speech recognition, conference calling, audio streaming, number masking, and DTMF.

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Where are recordings stored?

For detailed recording setup, see Record Calls Guide. Recordings are stored on Plivo servers, accessible via API or console, with download URLs provided in callbacks.

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How do I delete recordings?

Use the Recording API with the recording ID: 
DELETE /v1/Account/{auth_id}/Recording/{recording_id}/

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What about transcription support?

Plivo can automatically transcribe recordings in English only. Transcriptions may be blank for recordings shorter than 19 seconds.

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What is Automatic Speech Recognition?

For text-to-speech, see Speak XML Reference. ASR transcribes caller speech in real-time for IVR systems, voice search, and call transcription use cases.

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How do I integrate ASR?

Configure ASR in your application’s XML response or via streaming integration. See ASR documentation for supported languages and setup.

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How does AMD work?

Detects whether a call is answered by:
  • Human: Live person answered
  • Machine: Voicemail or IVR
  • Unknown: Detection inconclusive

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How do I enable AMD?

Use the Make Call API with parameters:
  • machine_detection: Enable/disable
  • machine_detection_time: Detection window in ms
  • machine_detection_url: Callback URL

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What are best practices for AMD?

  • Use async mode to avoid delays
  • Handle “unknown” results gracefully
  • Test with your call patterns

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How does number masking work?

For audio streaming, see Audio Streaming Guide. For conference calling, see Conference Guide.
  1. Create session with two parties
  2. Plivo assigns virtual number
  3. Party A calls virtual number → connects to Party B
  4. Neither party sees the other’s real number

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What are typical use cases for number masking?

  • Ride-sharing (driver ↔ passenger)
  • Delivery services
  • Marketplaces
  • Dating apps

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What are key session parameters?

ParameterDescription
virtual_numberPlivo proxy number
first_party/second_partyPhone numbers
session_expiryDuration
virtual_number_cooloff_periodReuse time
force_pin_authenticationRequire PIN

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Can I create sessions with only one party?

Yes, add the second party later via Sessions API.

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Are there additional costs for number masking?

Replacing sub-optimal numbers or extending sessions may incur additional charges.

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What triggers voice alerts?

  • Call failure spike (unusual increase)
  • Invalid XML (malformed responses)
  • High latency (exceeds threshold)
  • Traffic anomaly (unusual patterns)

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How do I configure voice alerts?

  1. Navigate to Voice > Settings > Alerts
  2. Enable alert types
  3. Configure thresholds
  4. Set notification preferences

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How do I send DTMF during a call?

For capturing DTMF input, see GetDigits XML. Use the DTMF API to send tones.

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What are DTMF limitations?

  • Not supported in China
  • Supported format: RFC-2833