call: subscribeToTone

Namespace: microsoft.graph

Subscribe to DTMF (dual-tone multi-frequency signaling) which allows you to be notified when the user presses keys on a "dialpad".


The subscribeToTone action is supported only for calls that are initiated with serviceHostedMediaConfig.

This API is available in the following national cloud deployments.

Global service US Government L4 US Government L5 (DOD) China operated by 21Vianet


Choose the permission or permissions marked as least privileged for this API. Use a higher privileged permission or permissions only if your app requires it. For details about delegated and application permissions, see Permission types. To learn more about these permissions, see the permissions reference.

Permission type Least privileged permissions Higher privileged permissions
Delegated (work or school account) Not supported. Not supported.
Delegated (personal Microsoft account) Not supported. Not supported.
Application Calls.AccessMedia.All Not available.

Note: Any tone data provided may not be persisted. Make sure you are compliant with the laws and regulations of your area regarding data protection and confidentiality of communications. Please see the Terms of Use and consult with your legal counsel for more information.

HTTP request

POST /communications/calls/{id}/subscribeToTone

Request headers

Name Description
Authorization Bearer {token}. Required.

Request body

In the request body, provide a JSON object with the following parameters.

Parameter Type Description
clientContext String Unique client context string. Can have a maximum of 256 characters.


If successful, this method returns 200 OK response code.


The following example shows how to call this API.


The following example shows the request.

Content-Type: application/json
Content-Length: 46

  "clientContext": "fd1c7836-4d84-4e24-b6aa-23188688cc54"

Note: The response object shown here might be shortened for readability.

HTTP/1.1 200 OK
Content-Type: application/json

  "@odata.type": "#microsoft.graph.subscribeToToneOperation",
  "clientContext": "clientContext-value",
  "id": "0fe0623f-d628-42ed-b4bd-8ac290072cc5",
  "status": "completed"
Notification - tone notification

The notification contains information of the tone pressed in the toneinfo resource.

Content-Type: application/json
  "@odata.type": "#microsoft.graph.commsNotifications",
  "value": [
      "@odata.type": "#microsoft.graph.commsNotification",
      "changeType": "updated",
      "resourceUrl": "/communications/calls/57dab8b1-894c-409a-b240-bd8beae78896",
      "resourceData": {
        "@odata.type": "",
        "state": "established",
        "toneInfo": {
          "@odata.type": "#microsoft.graph.toneInfo",
          "sequenceId": 1,
          "tone": "tone1"