Merge pull request #277761 from jamescadd/teams-interop-transfer-voicemail

Adds transfer to voicemail

Author: JamesJBarnett

articles/communication-services/concepts/interop/teams-user-calling.md

@@ -123,7 +123,7 @@ The following list presents the set of features that are currently available in
 |                   | Transfer a call to a user                                                                                           |   ✔️      | ✔️ | ✔️ | ✔️ |
 |                   | Be transferred to a user or call                                                                                     |   ✔️      | ✔️ | ✔️ | ✔️ |
 |                   | Transfer a call to a call                                                                                            |   ✔️      | ✔️ | ✔️ | ✔️ |
-|                   | Transfer a call to Voicemail                                                                                         |   ❌      | ❌ | ❌ | ❌ |
+|                   | Transfer a call to Voicemail                                                                                         |   ✔️      | ✔️ | ✔️ | ✔️ |
 |                   | Be transferred to voicemail                                                                                           |   ✔️      | ✔️ | ✔️ | ✔️ |
 |                   | Merge ongoing calls                                                                                                  |   ❌      | ❌ | ❌ | ❌ |
 |                   | Does start a call and add user operations honor shared line configuration                                            |   ✔️      | ✔️ | ✔️ | ✔️ |

articles/communication-services/how-tos/calling-sdk/includes/transfer-calls/transfer-calls-web.md

@@ -97,3 +97,52 @@ transfer.on('stateChanged', () => {
 });
 ```
 
+### Transfer to voicemail:
+
+1. There's already a connected call between the *transferor* and the *transferee*. 
+2. The Teams User Identifier of the *target participant voicemail* is known.
+3. The *transferor* decides to transfer the call with the *transferee* to the voicemail with *voicemail id*.
+4. The *transferor* calls the `transfer` API.
+6. The *transferee* receives the transfer request.
+
+To transfer a current call, you can use the `transfer` API.
+
+```js
+// transfer to the target call specifying the call id
+const id = { targetParticipantVoicemail: <TEAMS_USER_ID> };
+```
+
+```js
+// call transfer API
+const transfer = callTransferApi.transfer({ target: id });
+```
+
+The `transfer` API allows you to subscribe to `stateChanged`. It also comes with a  transfer `state` and `error` properties
+
+```js
+// transfer state
+const transferState = transfer.state; // None | Transferring | Transferred | Failed
+
+// to check the transfer failure reason
+const transferError = transfer.error; // transfer error code that describes the failure if a transfer request failed
+```
+
+The *transferee* can listen to a `transferAccepted` event. The listener for this event has a `TransferEventArgs` which contains the call object of the new transfer call
+between the  *transferee* and the *target participant voicemail*. 
+
+```js
+// Transferee can subscribe to the transferAccepted event
+callTransferApi.on('transferAccepted', args => {
+    const newTransferCall =  args.targetCall;
+});
+```
+
+The *transferor* can subscribe to events for change of the state of the transfer. If the call to the *transferee* was successfully connected with *target participant voicemail*, *transferor* can hang up the original call with *transferee*.
+
+```js
+transfer.on('stateChanged', () => {
+   if (transfer.state === 'Transferred') {
+       call.hangUp();
+   }
+});
+```

articles/communication-services/how-tos/calling-sdk/transfer-calls.md

@@ -15,7 +15,7 @@ ms.custom: template-how-to
 
 # Transfer calls
 
-During an active call, you may want to transfer the call to another person or number. Let's learn how. 
+During an active call, you may want to transfer the call to another person, number, or to voicemail. Let's learn how. 
 
 ## Prerequisites