dial

The dial verb is used to create a new call by dialing out to a telephone number, a registered sip user, a sip uri, or a Microsoft Teams user.

{
  "verb": "dial",
  "actionHook": "/outdial",
  "callerId": "+16173331212",
  "answerOnBridge": true,
  "dtmfCapture": ["*2", "*3"],
  "dtmfHook": {
    "url": "/dtmf",
    "method": "GET"
  },
  "target": [
    {
      "type": "phone",
      "number": "+15083084809"
    },
    {
      "type": "sip",
      "sipUri": "sip:1617333456@sip.trunk1.com",
      "auth": {
        "user": "foo",
        "password": "bar"
      }
    },
    {
      "type": "user",
      "name": "spike@sip.example.com"
    }
  ]
}

As the example above illustrates, when you execute the dial command you are making one or more outbound call attempts in an effort to create one new call, which is bridged to a parent call. The target property specifies an array of call destinations that will be attempted simultaneously.

If multiple endpoints are specified in the target array, all targets are outdialed at the same time (e.g., "simring", or "blast outdial" as some folks call it) and the call will be connected to the first endpoint that answers the call (or, optionally, the first call that completes a call screening application as specified in the confirmHook property).

There are several types of endpoints that you can dial:

  • a telephone phone number -- this call attempt will be sent out through your configured Carrier,
  • a webrtc or sip client that has registered directly with your subdomain,
  • a sip endpoint, identified by a sip uri (and possibly authentication parameters), or
  • Microsoft Teams user

You can use the following attributes in the dial command:

option description required
actionHook webhook to invoke when the call ends. The webhook will include properties describing the outcome of the call attempt. no
answerOnBridge If set to true, the inbound call will ring until the number that was dialed answers the call, and at that point a 200 OK will be sent on the inbound leg. If false, the inbound call will be answered immediately as the outbound call is placed.
Defaults to false.
no
callerId The inbound caller's phone number, which is displayed to the number that was dialed. The caller ID must be a valid E.164 number.
Defaults to caller id on inbound call.
no
confirmHook webhook for an application to run on the callee's end after the dialed number answers but before the call is connected. This allows the caller to provide information to the dialed number, giving them the opportunity to decline the call, before they answer the call. Note that if you want to run different applications on specific destinations, you can specify the 'url' property on the nested target object. no
dialMusic url that specifies a .wav or .mp3 audio file of custom audio or ringback to play to the caller while the outbound call is ringing. no
dtmfCapture an array of strings that represent dtmf sequence which, when detected, will trigger a mid-call notification to the application via the configured dtmfHook no
dtmfHook a webhook to call when a dtmfCapture entry is matched. This is a notification only -- no response is expected, and any desired actions must be carried out via the REST updateCall API. no
headers an object containing arbitrary sip headers to apply to the outbound call attempt(s) no
listen a nested listen action, which will cause audio from the call to be streamed to a remote server over a websocket connection no
target array of to 10 destinations to simultaneously dial. The first person (or entity) to answer the call will be connected to the caller and the rest of the called numbers will be hung up. yes
timeLimit max length of call in seconds no
timeout ring no answer timeout, in seconds.
Defaults to 60.
no
transcribe a nested transcribe action, which will cause the call to be transcribed no
target types

PSTN number

option description required
type must be "phone" yes
confirmHook A webhook for an application to run on the callee's end after the dialed number answers but before the call is connected. This will override the confirmHook property set on the parent dial verb, if any. no
number a telephone numnber in E.164 number yes

sip endpoint

option description required
type must be "sip" yes
confirmHook A webhook for an application to run on the callee's end after the dialed number answers but before the call is connected. This will override the confirmHook property set on the parent dial verb, if any. no
sipUri sip uri to send call to yes
auth authentication credentials no
auth.user sip username no
auth.password sip password no

Using this approach, it is possible to send calls out a sip trunk. If the sip trunking provider enforces username/password authentication, supply the credentials in the auth property.

a registered webrtc or sip user

option description required
type must be "user" yes
confirmHook A webhook for an application to run on the callee's end after the dialed number answers but before the call is connected. This will override the confirmHook property set on the parent dial verb, if any. no
name registered sip user, including domain (e.g. "joeb@sip.jambonz.org") yes

Microsoft Teams user

If Microsoft Teams integration has been configured, you can dial out to Teams users.

option description required
type must be "teams" yes
tenant Microsoft Teams customer tenant domain name. Will default to the Microsoft Teams tenant associated with the account of the calling party. no
number the phone number that has been mapped to the teams user by the Microsoft Teams administrator yes
voicemail if true, dial directly into user's voicemail to leave a message no

The confirmHook property that can be optionally specified as part of the target types is a web callback that will be invoked when the outdial call is answered. That callback should return an application that will run on the outbound call before bridging it to the inbound call. If the application completes with the outbound call still in a stable/connected state, then the two calls will be bridged together.

This allows you to easily implement call screening applications (e.g. "You have a call from so-and-so. Press 1 to decline").

actionHook properties

The actionHook that is invoked when the dial command ends will include the following properties:

property name description
dial_call_sid the unique call_sid identifier for the child call
dial_status the final status of the call attempt, one of 'completed', 'failed', 'busy', 'no-answer', or 'queued'
dial_sip_status the sip status of the final response to the INVITE that was sent

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