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`	RECOMMENDED 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`

Sample Dial Request

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"
}

General order of operations

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

Please Note: At any point, the callee could hangup generating a call.hangup webhook.

`call.machine.detection.ended` Webhook

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

{
  "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"
  }
}

`call.machine.greeting.ended` Webhook

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

{
  "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"
  }
}

Answering Machine Detection

AMD Settings

Sample Dial Request

General order of operations

call.machine.detection.ended Webhook

Sample Webhook

call.machine.greeting.ended Webhook

Sample Webhook

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`call.machine.detection.ended` Webhook

`call.machine.greeting.ended` Webhook