Question
How accurate is answering machine detection?
Applies To
- Voice API
- Answering Machine Detection
Answer
We use a Call Progress Analyzer (CPA) for answering machine (voicemail) detection. While there is no consistent signaling difference between a call picked up by a human or a machine, we detect voicemail using data from the tone of voice and the speed of words spoken. This detection usually takes 3 to 5 seconds. Vonage's machine detection typically has an accuracy on par with industry standards, where 60% to 80% of calls can detect an answer machine correctly.
If a machine is detected during this time and machine_detection is set to hangup, the call hangs up immediately and the status parameter value sent back to your webhook URL will be set to machine.
Machine detection for Google Voice numbers is not supported due to the short greeting on the initial answer of the voicemail. Due to the length of the message, this is recognized as being answered by a person and so the call will continue.
Articles in this section
- Do we retry if the voice event webhook fails?
- How do I verify that the Voice API Webhook request and it's payload has not been tampered during transit?
- How To Check Call Quality With Voice Inspector
- What is a Conversation ID?
- How to configure the custom webhook timeout for Voice API functionality and what are the allowed timeout ranges ?
- How do I change TTL for the Conversations and Call Legs?
- Why are call progress events not being received on the Event URL defined in the conversation action NCCO?
- Why is there an extended silence at the beginning of a call and how can it be reduced?
- Intermittent WebSocket Disconnections
- What Is An NCCO