One of the Exchange Server PMs on the Front-End team shared this cool tip for disabling the Play on Phone capabilities of Exchange 2007 Unified Messaging.
The Exchange 2007 Unified Messaging Play on Phone feature enables a UM-enabled user to access a voice mail message. However, instead of playing the media file over their computer speakers, they can listen to the message on a telephone.
When users sit in office cubicles, use a public computer, have a computer that is not enabled for multimedia, or have a voice message that is confidential, a UM-enabled user may not want to or may be unable to play a voice message over their computer speakers. The Play on Phone feature lets the UM-enabled user play the voice message over a telephone. The Play on Phone feature is available in Exchange 2007 Outlook Web Access and in Office Outlook 2007.
To disable Play on Phone without affecting any other Unified Messaging functionality you set the OutCallsAllowed property on all UMIpGateway objects to false. For example:
set-UMIPGateway NameofGateway -OutCallsAllowed $false
You can also navigate to the Properties dialog for the IP Gateway object and uncheck the check box for Allow Outgoing Calls.
The flag instructs the Unified Messaging server to never to send SIP Invites (new calls) to the corresponding gateway object. If there are no gateway objects with the property set to true, then Unified Messaging will not attempt to place any outbound calls.
When using this tip, be aware that:
For more information about Play on Phone, see http://technet.microsoft.com/en-us/library/bb124387.aspx.
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