Rick,
Here is the document to the Unity System requirements.
http://www.cisco.com/univercd/cc/td/doc/product/voice/c_unity/unity42/42reqs.htm
?A supported version of Microsoft Windows Server 2003 or Windows 2000 Server:
?Windows Server 2003 R2 Enterprise Edition (requires Exchange Server 2003 as the message store)
?Windows Server 2003 R2 Standard Edition (requires Exchange Server 2003 as the message store)
?Windows Server 2003 Enterprise Edition (requires Exchange Server 2003 as the message store)
?Windows Server 2003 Standard Edition (requires Exchange Server 2003 as the message store)
?Windows 2000 Server
?Windows 2000 Advanced Server
If you are looking for the AD Domain heirarchy that is supported then reference the Unity Design Guide. This document hasn't been updated since 4.0(3).
http://www.cisco.com/univercd/cc/td/doc/product/voice/c_unity/design/udg/udg403.pdf
Please rate any helpful posts
Thanks
Fred
