In this article I spoke about how to configure the Exchange 2010 side of Unified Messaging with Cisco Call Manager:
I wanted to point out this issue in a separate article because it seems a decent amount of people are having the same issue.
After we configured Exchange 2010 UM with Cisco Call Manager, we got a fast busy signal when calling the users voicemail. After turning up diagnostic logging on all of the Exchange UM servers, we would see the SIP connection hit:
But the user would get a fast busy, and we saw event ID 1006 in the event log, which stated The Unified Messaging server has ended a call with ID … because the user at the far end disconnected
We checked the trunk between Exchange and CCM, and it was set to the G.711 codec (as Exchange doesn’t support G.729).
After some digging inside the call manager, I changed this setting inside Cisco Call Manager:
Select one of your call manager servers, and select the serviceCisco CallManager (Active):
Change the Default Interregion Max Audio Bit Rate from the default setting of 8 kbps (G.729) to 64 kbps (G.722, G.711).
After this change, everything worked!