If you’re looking to restrict Skype/Lync Mobile Clients from
dialing PSTN numbers and allow Enterprise Voice enabled users to make PSTN calls
only via Desktop Clients you will need to set a mobility policy.
Set-CsMobilityPolicy -Identity “site:Redmond” –EnableIPAudioVideo $False
When set to “False”, prohibits the user from making Lync
voice calls using the mobile device by removing the dial pad option from the
Lync client. The default value is “True”, meaning that VoIP calls are allowed.
Additionally you can disable "Call via work" for
this policy as well. Call via work is the feature that if enabled will allow
mobile users to make PSTN calls through your PBX. So if you want to block all PSTN calls your command would
look like this;
Set-CsMobilityPolicy -Identity “site:Redmond” –EnableIPAudioVideo $False -EnableOutsideVoice $False
