One basic use of Skype for Business Server is instant messaging (IM) and presence within a single organization.

Skype for Business Server uses Interactive Connectivity Establishment for NAT traversal and TLS encryption to enable secure voice and video both inside and outside the corporate network.

The communicator client also uses HTTPS to connect with the web components server to download address books and expand distribution lists.

Microsoft has published details of supported configuration for qualified vendors through Unified Communications Open Interoperability Program (UCOIP).

OCS R2 was announced at VoiceCon in Amsterdam in October 2008,[8] a year after releasing Office Communications Server 2007.

[9] The R2 release added the following features:[10] Microsoft Lync Server 2010 reached general availability in November 2010.

In 2015, the new version of Lync became Skype for Business with a new client experience, new server release and updates to the service in Office 365.

This client is used for IM, presence, voice and video calls, desktop sharing, file transfer and ad hoc conferences.

Persistent Group Chat functionality (introduced with Lync Server 2010[13][14]) is only supported on the Windows OS client at this time.

[26][27] Microsoft announced that effective 30 June 2014, they will no longer support PIC connectivity to AOL/AIM[28] As of 2012[update], the third-party SIPE plugin enables third-party clients such as Pidgin, Adium and Miranda NG as well as clients using the Telepathy framework to support MS Lync Servers with some limitation (Audio but no SRTP, No Video) via the extended version of SIP/SIMPLE.

Products such as Cisco Unified Presence Server (Version 6.0.2+) support federation with Microsoft Office Communication Server 2007 to provide presence of Cisco IP phones and remote call control of the IP phone from the Microsoft Office Communicator client.