Consider the following scenario:
- User A uses a Microsoft Office Communicator 2007 R2 client to log on to a Lync Server 2010 environment.
- The Public Instant Messaging (IM) Connectivity (PIC) feature is enabled in the Lync Server 2010 environment.
- User B is using a public IM client, such as Windows Live Messenger, AOL, or Yahoo. User B types in the Session Initiation Protocol (SIP) Uniform Resource Identifier (URI) of user A.