Conferences work well if all attendees have access to client-access components, such as Microsoft Office Communicator, but there are often situations where someone needs to attend but doesn’t have access to these components, such as a user who may be temporarily out of the office without computer access. To enable such users to participate in a conference, you can deploy dial-in conferencing. This feature enables users to use a public switched telephone network (PSTN) phone to join the audio portion of an on-premises Web conference, without requiring your organization to use the services of a third-party audio conferencing provider.

Dial-in conferencing is implemented by two Office Communications Server applications: Conferencing Attendant and Conferencing Announcement Service. By dialing an access number that maps to the Conferencing Attendant SIP URI and then entering a conference ID, dial-in conferencing users are added to the conference participant list when they join a conference. Conferencing Announcement Service plays entry and exit tones to announce when a phone user joins or leaves a conference. Furthermore, users of dial-in conferencing who have Active Directory credentials can be authenticated and, subsequently, listed in a conference participant list by name. Conference leaders can exercise conference controls on all users in a participant list, including dial-in conferencing users, and conference participants who joined the conference using a Communicator client can view the participant list to see who is in attendance. Conferencing Announcement Service also announces when a phone user has been muted or unmuted.

Dial-in conferencing can be used for scheduled meetings or unscheduled meetings. If your organization uses Microsoft Office Outlook, you can deploy the Conferencing Add-in for Outlook to enable users to schedule on-premises Web conferences. Meeting invitations that are created using the add-in include conference access information for dial-in conferencing users. Conferencing Attendant uses the same meeting policies that you configure for Web conferencing. Depending on the level of access that you configure for meetings, A/V conferences can include authenticated dial-in conferencing users who are users inside or outside your organization’s firewall, anonymous users without Active Directory credentials, or both.

In addition to determining whether A/V conferencing with support for dial-in conferencing is required by your organization, you also need to determine whether you need to support Enterprise Voice or anonymous users. Dial-in conferencing can be deployed in your organization whether or not you deploy Microsoft’s software-powered Voice over IP (VoIP) solution, Enterprise Voice.

For a feature overview of Conferencing Attendant and Conferencing Announcement Service, see New Dial-in Conferencing Featureand Dial-in Audio Conferencing in Office Communicator, which are both topics in New Server Features in the Getting Started documentation.

For a technical overview of Conferencing Attendant and Conferencing Announcement Service, see Dial-in Conferencing Architecturein New Server Features in the Getting Started documentation.