Microsoft Skype for Business (SfB) Unified Communication and Exchange Server

Skype for Business is a communications and collaboration platform that brings together the client experience with enterprise-grade security, compliance, and control.
SfB features includes: presence, instant messaging (IM), enterprise voice and video calls, application sharing, and online meetings.

Exchange server features consist of electronic mail, calendaring, contacts, integration support for SfB and support for mobile and web-based information access.