The primary client software for Office Communications Server 2007 R2 is Microsoft Office Communicator 2007 R2. Office Communicator supports placing and receiving calls, enhanced presence, instant messaging (IM), and multimodal conferencing features.

The Microsoft Office Live Meeting client is a data collaboration and audio/video (A/V) client for both Office Communications Server and the hosted Microsoft Live Meeting service. It enables users to participate in meetings.

The Conferencing Add-in for Microsoft Office Outlook is a conference scheduling client for Office Communications Server.

Office Communications Server 2007 R2 Attendant is an integrated call management application that enables a user to manage many conversations at once through rapid call handling, IM, and on-screen routing. It is intended primarily for users who must manage multiple calls at once, including receptionists and administrative assistants.

Microsoft Office Communications Server 2007 R2 Group Chat is the group chat client that is used to post and access channel content, including files, links, and text, as well as to exchange IM between two users.