Microsoft has provided a UM Test Phone that allows you to test UM functionality without having a real PBX installed. The guide for setting this up is located here. Part of the guide is for obtaining the .exe for the UM Test Phone as well as obtaining all the .dll files needed to ensure the UM Test Phone works. That information is located here. This can be a little time consuming gathering all the necessary files required. Since I did that, I figured I would package up the umtestphone.exe file as well as the .dll files so you, the reader, do not have to bother with this.
I just want to stress that I take no responsibility for anything that goes wrong from you running this in your environment. I suggest using it only in a segregated test environment to ensure that if something does go wrong, it does not affect production. You use the contents of the provided packaged file at your own risk.
Update (11/25/2009): The UM Test Phone works fine against Exchange 2010 UM as I just tested it. The UM Test Phone does not work on Windows 7 even with Windows Compatibility Settings configured on the executable. You can use Windows XP Mode with a bridged NIC. Windows XP Mode will use your computers audio speakers and things will work well. I’m not sure if the application works on Windows Vista as I have never tested it on Windows Vista.
Here is a screenshot of the contents of the zip file opened in WinRAR:
You can download the packaged .zip file here.