This is a simple script you can use to see which server has active calls (mediation).

This uses the Get-CsWindowsService cmdlet to get the RTCMEDSRV values. This can be useful if you need to restart a server.

If you need only one server, you can also use this command :

Get-CsWindowsService -Name RTCMEDSRV | select activitylevel

To launch the function, just write the function name followed by the computername :

Get-CsActiveCalls computer01,computer02,computer03,computer04

This will show you the active calls like in the picture.

A few modifications : powershell seems to keep all values from before, so we just clear the values after showing the object with Clear-Item.

Communication Server versions tested
Office Communication Server 2007
Microsoft Lync Server 2010 OK
Microsoft Lync Server 2013 OK

Here is the script :