Answering Machine Detection

Outbound calls placed with Call Control can be enabled with Answering Machine Detection (AMD, Voicemail Detection).

When a call is answered, Telnyx runs real-time detection to determine if it was picked up by a human or a machine and sends webhooks with the analysis result.

AMD Settings

The answering_machine_detection value when creating an outbound call or transferring an inbound call can be set to one of the following:

Setting Description Webhooks Sent
detect Only detect if answering machine or human. call.machine.detection.ended
detect_beep Listens for a final "beep" sound after detecting a machine call.machine.detection.ended and call.machine.greeting.ended only if a beep is detected
detect_words After a machine is detected, a 30 second long beep detection will begin. Note the answering machine may still be playing it's greeting while the 30 seconds is counting down. call.machine.detection.ended and call.machine.greeting.ended when the beep is detected or at the end of 30 seconds.
greeting_end Listens for extended periods of silence or a beep in the greeting to determine if a greeting has ended. call.machine.detection.ended and call.machine.greeting.ended
premium RECOMMENDED Premium AMD uses advanced speech recognition technology and machine learning to achieve exceptional accuracy in determining whether a call has been connected to a live person or a machine. call.machine.premium.detection.ended with one of human_residence or human_business or machine or silence or fax_detected or not_sure. If a beep is detected a call.machine.premium.greeting.ended webhook with beep_detected is also sent. If a beep is detected before call.machine.premium.detection.ended, call.machine.premium.greeting.ended is sent. If a beep is detected after call.machine.premium.detection.ended, both webhooks will be sent.

Sample Dial Request

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POST https://api.telnyx.com/v2/calls HTTP/1.1
Content-Type: application/json; charset=utf-8
Authorization: Bearer YOUR_API_KEY

{
  "connection_id" : "1494404757140276705",
  "to"            : "+19198675309",
  "from"          : "+19842550944",
  "webhook_url"   : "https://webhook_url.com/outbound_call_events",
  "answering_machine_detection" : "detect_words"
}

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General order of operations

  1. Create outbound call.
  2. Receive call.initiated webhook.
  3. Receive call.answered webhook when the call is answered either by human or machine.
  4. Receive call.machine.detection.ended webhook with human/machine status.
  5. Receive call.machine.greeting.ended webhook when beep detected or 30 second timeout.

x. Important at any point, the callee could hangup generating a call.hangup webhook.

Webhooks

call.machine.detection.ended

The call.machine.detection.ended is sent when Telnyx can make a determination on human or machine.

The data.payload.result will contain the information about the answering machine:

Result Description
human Human answered call
machine Machine answered call
not_sure Recommended to treat as if human answered.

Sample Webhook

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{
  "data": {
    "event_type": "call.machine.detection.ended",
    "id": "0ccc7b54-4df3-4bca-a65a-3da1ecc777f0",
    "occurred_at": "2018-02-02T22:25:27.521992Z",
    "payload": {
      "call_control_id": "v2:T02llQxIyaRkhfRKxgAP8nY511EhFLizdvdUKJiSw8d6A9BborherQ",
      "call_leg_id": "428c31b6-7af4-4bcb-b7f5-5013ef9657c1",
      "call_session_id": "428c31b6-abf3-3bc1-b7f4-5013ef9657c1",
      "client_state": "aGF2ZSBhIG5pY2UgZGF5ID1d",
      "connection_id": "7267xxxxxxxxxxxxxx",
      "from": "+35319605860",
      "result": "machine",
      "to": "+13129457420"
    },
    "record_type": "event"
  }
}

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call.machine.greeting.ended

If the answering_machine_detection was set to detect_beep, detect_words, greeting_end you could receive a final webhook when the prompt (or beep detection) has finished.

The data.payload.result will contain the information about the answering machine:

Result Description AMD Setting
ended Greeting is over. ONLY sent when setting is greeting_end
beep_detected Beep has been detected detect_beep and detect_words
not_sure 30 second beep detection timeout fired after detecting a machine detect_beep and detect_words

Sample Webhook

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{
  "data": {
    "event_type": "call.machine.greeting.ended",
    "id": "0ccc7b54-4df3-4bca-a65a-3da1ecc777f0",
    "occurred_at": "2018-02-02T22:25:27.521992Z",
    "payload": {
      "call_control_id": "v2:T02llQxIyaRkhfRKxgAP8nY511EhFLizdvdUKJiSw8d6A9BborherQ",
      "call_leg_id": "428c31b6-7af4-4bcb-b7f5-5013ef9657c1",
      "call_session_id": "428c31b6-abf3-3bc1-b7f4-5013ef9657c1",
      "client_state": "aGF2ZSBhIG5pY2UgZGF5ID1d",
      "connection_id": "7267xxxxxxxxxxxxxx",
      "from": "+35319605860",
      "result": "ended",
      "to": "+13129457420"
    },
    "record_type": "event"
  }
}

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AMD Premium Webhooks

call.machine.premium.detection.ended

The call.machine.premium.detection.ended webhook is sent when the AMD process can determine whether the call was answered by a human or a machine. If the timeout is reached before the result is available, the result will be not_sure.

The data.payload.result will contain the information about the answering machine:

Result Description
human_residence A human answered the call
human_business A human answered call
machine A machine answered the call
silence No sound was detected
fax_detected A Fax machine answered the call
not_sure Not identifiable, or the configured AMD timeout was reached before the result was available.

Sample Webhook

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{
  "data": {
    "event_type": "call.machine.premium.detection.ended",
    "id": "0ccc7b54-4df3-4bca-a65a-3da1ecc777f0",
    "occurred_at": "2018-02-02T22:25:27.521992Z",
    "payload": {
      "call_control_id": "v2:T02llQxIyaRkhfRKxgAP8nY511EhFLizdvdUKJiSw8d6A9BborherQ",
      "call_leg_id": "428c31b6-7af4-4bcb-b7f5-5013ef9657c1",
      "call_session_id": "428c31b6-abf3-3bc1-b7f4-5013ef9657c1",
      "client_state": "aGF2ZSBhIG5pY2UgZGF5ID1d",
      "connection_id": "7267xxxxxxxxxxxxxx",
      "from": "+35319605860",
      "result": "machine",
      "to": "+13129457420"
    },
    "record_type": "event"
  }
}

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call.machine.premium.greeting.ended

If a machine answered the call, you may receive a final webhook when the beep detection has finished. This webhook is optional and will only be sent if one of two happens:

  • a beep is detected. In this case, the result is beep_detected .
  • the optional AMD timeout is reached after the call was answered by a machine , but no beep was heard. For this case, the result is no_beep_detected .

The data.payload.result will contain the information about the answering machine:

Result Description AMD Setting
beep_detected Greeting is over. ONLY sent when a machine answered the call, and a beep was heard.
no_beep_detected ONLY sent when a machine answered the call, and the AMD timeout was reached before a beep was heard.

Sample Webhook

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{
  "data": {
    "event_type": "call.machine.premium.greeting.ended",
    "id": "0ccc7b54-4df3-4bca-a65a-3da1ecc777f0",
    "occurred_at": "2018-02-02T22:25:27.521992Z",
    "payload": {
      "call_control_id": "v2:T02llQxIyaRkhfRKxgAP8nY511EhFLizdvdUKJiSw8d6A9BborherQ",
      "call_leg_id": "428c31b6-7af4-4bcb-b7f5-5013ef9657c1",
      "call_session_id": "428c31b6-abf3-3bc1-b7f4-5013ef9657c1",
      "client_state": "aGF2ZSBhIG5pY2UgZGF5ID1d",
      "connection_id": "7267xxxxxxxxxxxxxx",
      "from": "+35319605860",
      "result": "beep_detected",
      "to": "+13129457420"
    },
    "record_type": "event"
  }
}

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