We recently ran into a problem with one of my customers around Lync Dialin Conferencing. The problem was around using the “Call me at:” feature while joining the audio portion of Lync online meetings.
Unfortunately we found out that in order for this dial back to succeed either the organizer or the participant must be enabled for Enterprise Voice (EV) in Lync. If neither users are enabled for EV then you will get an error at the bottom of the client saying it couldn’t connect.
There is one way to get around the requirement of being EV enabled but it’s not supported. You can add a static route to the mediation server which would allow all outbound calls. The drawback is now you have just given any Lync client the ability to call any phone number. Probably not the best idea. So there really isn’t any way to accomplish this that is supported besides EV enabling your users…until….Lync 2013!
With the release of Lync 2013 gives us a new feature called “Dail-out Conferencing for non-Enteprise Voice users”. This can be configured by setting the Conferencing policy to allow this feature (Set-CSConferencingPolicy –AllowNonEnterpriseVoiceUsersToDialOut:$true). After enabling this you can then assign a voice policy to this user and they will be able to take advantage of this feature. Another Great reason to upgrade to Lync 2013 :)