Applies To

Call2Teams - Customers/Partners


Phone App provides a Native Teams call through the core Microsoft SIP Gateway. However, due to the functionality of the Phone App not licensing the Microsoft Phone System, some call controls are managed within the Phone App. 

Users will notice that as the call is still a native Teams call, some call controls will be available but may not have the desired behaviour.


Phone App uses the following Microsoft API to get the personal contacts of the user: 

These are usually reflected in the Teams client, and the contacts tab in the outlook client for the user.

More information here: PhoneApp and Contacts

In Phone App v1.2 this increased graph permission requires the user to rerun sync (highlighted item 1 in the screenshot below), and re-grant authority (highlighted item 2 in the screenshot below):

Functionality: Outbound Calls

Summary of how outbound click-to-dial works:

  1. HTTP request from the Teams application reaches our Call starter script.
  2. This script makes a call out to our network using some special headers that present as the real customer PBX for a specific user.
  3. This outbound call goes back through our network, to Teams, like a normal inbound call in terms of SIP flow.
  4. Once the call connects, a script deploys a REFER message. 
  5. This then goes through our network again, which bridges out a new call.
  6. The system then calls the real number.

Functionality: Hold / Off Hold

In an active Phone App call, users have the option to put the call on hold (highlighted in the screenshot below) via the Phone App main window. 

The Phone App will mimic the same Hold scenario as in Direct Routing; sending an A=Inactive to the Teams Client and back to the PBX. 

This means that if the customer's PBX supports MOH (music on hold) with Direct Routing then it will work as expected.

To resume the call, the Active calls window button changes to Resume allowing users to take the call off hold. 

Functionality: Transfer to PSTN

Phone App users have the ability to transfer an active call back out to the PSTN through the PBX. 

This behaviour works with the service infrastructure sitting in the middle of the call path between the Teams Client (Party B) and the customer's PBX (Party A). 

Calls transfers using Phone App are blind operations, so have no ability to retrieve the call once the transfer button is pressed. This is because the REFER is handed back to the customer's PBX with Party A now connected to the transferred number (Party C).


Please note Destiny Automate Ltd. (formerly Qunifi Limited) cannot be held responsible for the content of any third-party documentation offered.