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Instant Messaging

Collaboration through the use of IMs has been a part of Lync Server since the beginning along with presence. Although IMs are a simple mode of communication, they can be an excellent way to conduct a conversation in a quick manner without needing to resort to email or a phone call.

In Lync Server, IM is not unlike IM conversations that use other providers, but the main advantage to IM with Lync Server instead of a public solution is that by default all messaging is encrypted through TLS connections to the servers and an organization has complete control over how the system is used. This means that a rogue user on your network can’t start a packet sniffer application and read messages sent between two other users.

The Lync Server endpoints support the same kind of features found in many other IM clients, such as rich text, emoticons, and saving messages. The end user and security features enable an organization to standardize on a single messaging client such as Lync instead of multiple clients and services.

Web Conferencing

Lync Server gives users the ability to create or join virtual meetings referred to as web conferences, including attendees from inside the organization or guest users without an account in the Communications Server environment. Lync Server 2012 adds additional features to the Web Conferencing Web Client such as voice and video over IP from the browser. These capabilities are discussed in depth in Chapter 26, “Browser Client.” Overall, many of the same features from the previous release exist, and some additional capabilities have been added. These new capabilities are discussed in Chapter 2, “What’s New in Microsoft Lync Server 2013,” and throughout Part IX, “Clients.”

Audio and Video Conferencing

Organizations can leverage Lync Server to provide audio and video (A/V) conferencing services to their users without deploying additional clients or software. Deploying A/V conferencing enables users to perform peer-to-peer or multiparty conferences using high-fidelity audio and video conducted across the IP network. Users have a consistent experience because they can make and receive A/V calls through the same Lync client used for presence, IM, and web conferencing. Although A/V conferencing is sometimes linked to Enterprise Voice features, it can be deployed separately from any kind of telephony integration.

With video conversations, both peer-to-peer and multiparty video conversations can negotiate to use high-definition video quality using either Microsoft RTVideo or H.264 SVC/AVC.

Organizations have a wide variety of webcams to select what is compatible with Lync Server, and Microsoft provides a continuously updated list of certified devices. In Lync Server, video endpoints such as the Polycom CX5000 can be used in Lync to provide a full 360-degree panoramic view of the room.

Lastly, Lync Server video endpoints can be integrated with video conferencing systems from vendors such as Polycom, LifeSize, and Cisco.

Dial-In Conferencing

In addition to web or A/V conferencing, Lync Server can act as a conferencing bridge service for users. This enables individuals to schedule or launch an audio conference using a mix of Lync Server users and endpoints with users dialing in to a conference using traditional phone lines. Local numbers can be provided by region, or organizations can provide a toll-free number associated with one or many regions to external participants.

The dial-in conferencing service can be used as a standalone system or in conjunction with the web conferencing components of Lync Server to enable users to bridge PSTN audio with any web conference being conducted.

Dial-in conferencing also has no dependency on Enterprise Voice services for users, meaning users do not need to be enabled for Enterprise Voice to use the audio conferencing service. A user can be enabled simply for IM and presence, but also to schedule and join dial-in conferences through the Lync client or PSTN. Enterprise Voice users can also use the conferencing service, but being enabled for Enterprise Voice does not provide additional audio conferencing features from a user perspective.

The Lync Server conference bridge has a number of added benefits over a traditional conferencing service, as covered in the following sections.


Users can adjust the permissions for each conference to prevent specific types of attendees from participating. This gives end users the option to prevent meetings from being forwarded or from being accessed by anonymous participants on a per-meeting basis.

Flexible Conference IDs

When this is enabled for Lync Server, users are assigned a static, unique conference ID that is used for all of their meetings. A user’s conference ID is persistent by default, but if a user has back-to-back meetings, it is beneficial to schedule the second meeting with a unique ID. End users can do this easily when creating a conference, and it helps to prevent attendees from the second meeting from joining the first meeting if it runs to the end of the time slot.


The Lync Server lobby feature can be considered a type of waiting room where meeting attendees can be held before the meeting begins. As a presenter, the meeting can be configured to automatically admit all attendees from the lobby, admit only authenticated corporate users from the lobby, admit only authenticated corporate users invited specifically by the organizer, or admit no user from the lobby without manual acceptance. Attendees are allowed to join the meeting, but when held in the lobby, they are unable to hear the presenter or other users. The meeting organizer has the ability to allow or not allow attendees waiting in the lobby to attend the meeting.

As the organizer, participants are listed in the visual roster. Authenticated users show a display name, and users joining from the PSTN can display the phone number they dialed in from. Lync Attendee or Lync Web App users can enter a display name, which is shown in the roster, too.


Typical conferencing services prompt a user to record his name, business name, or possibly location when dialing in to a meeting from the PSTN, and then the user can play that recorded greeting as he enters or leaves the conference. In Lync Server, where a visual roster is available to all participants, the need for this service is greatly diminished and can become a distraction to the actual meeting as attendees enter and leave.

Organizers can enable or disable the announcement service on a per-meeting basis, and it is disabled by default. Attendees who dial in from a PSTN telephone and want to hear a roster might use Dual-Tone Multi-Frequency (DTMF) tones to request a roll call, which is played only to the attendee. Additionally, the conferencing service aggregates announcements when batches of users enter or leave at the same time and make an announcement such as “Eight users are leaving” instead of announcing each user individually.


Administrators can define regions, and dial-in numbers for the regions can be associated with specific language support. If multiple languages are associated with the region, users are presented with the option to select a language when joining via the PSTN. This enables users who speak different primary languages to participate in a single audio conference and hear menu or announcement recordings conducted in their selected language.

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