I’m trying to interface an IP PBX with an Exchange UM Auto Attendant. I’m using an SBC between the two and everything is working except for one problem.
When the Exchange UM Auto Attendant initiates a call transfer, to transfer the incoming call to the desired extension, it only uses a REFER method. The IP PBX does handle the call transfer just fine, but since a re-invite is not sent from the Exchange server to the IP PBX, the incoming call is not placed on hold during the call transfer, so the incoming caller hears nothing - silence.
Can Asterisk handle something like this, where the REFER would initiate the call transfer and the incoming call would be placed on hold, all ‘triggered’ by the REFER method from the Exchange server?