A bit of PowerShell to allow you to add a PSTN Usage to the list of PSTN Usages assigned to a Cs Voice Policy, inserted in the position you indicate.

The changes that you make are logged, including the resultant set of PSTN Usages and a back-out command that you can execute to undo the changes.

You can read more here https://blog.bumpinthe.net/2017/07/18/inserting-a-pstn-usage-into-a-voice-policy/

 

Updated 7/28/2017 to fix a bug tracked down by Greig Sheridan (www.greiginsydney.com) where the script would fail if the existing usage list only have one usage.