LYNC is the third release of Microsoft’s Unified Communications (UC) Suite. It comprises the following capabilities:
Instant Messaging (IM)
Point-to-Point Voice-over-Internet Protocol (VoIP) audio and video
Replacement or integration with traditional telephony infrastructure, also known as Enterprise Voice (available only with Lync on-premises)
Lync is a viable Private Branch eXchange (PBX) and traditional voice integration or replacement option when implemented ...