Applies To




An explanation of the different propagation REFER options:

PBX Handles Transfer

A REFER will get sent upstream to the PBX. The 'Refer-To' header contains a phone number and user=phone URI parameter.

Teams Handles Transfer

When using this version to transfer a call, a REFER message is not sent upstream to the PBX. 

From the customer portal perspective, it will appear as though a new call has been established.

Teams True Transfer

When using Teams True Transfer mode, a call is transferred directly within Teams to another Teams user, the call is also transferred in the background to the destination user on the PBX.


  • Provides correct off-hook busy representation of both users after a transfer
  • Enhances the attended transfer experience for users, especially where transferring to a call queue agent
  • Means users are free to take the next call following transfer 
  • Ensures compliance, integration, reporting and recording is applied to the correct agent
  • Means both the user’s SIP phone and PBX Voicemail will ring and be active following a Teams-to-Teams transfer

These benefits make Teams True Transfer essential for multi-agent queues and Call Center environments.

Note: Teams True Transfer should not be used in environments where a large number of users are not connected to the PBX as the transfer to another Teams user will not complete satisfactorily. In these scenarios use one of the alternative transfer modes.