The UM troubleshooting tool is a diagnostic commandlet which helps Exchange UM administrators to identify mis-configurations in telephony equipment and Exchange 2010 SP1 Unified Messaging settings. It emulates calls and runs a series of diagnostic tests, stating the reason and possible solutions for issues that have been detected.

To get started with the tool type the following:

Get-help Test-ExchangeUMCallFlow -detailed

You can download the tool from here:

http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=10d2e48f-0846-40b6-b08f-d282309811a2