Unified Communications (UC) is the integration of practically all real time communication services with the purpose of making communication more efficient. UC services include telephony, instant messaging, presence information and unified messaging (email, fax, SMS). As shown on the graphic below, UC unifies even the different core technologies, as telephony can be further divided into Voice over IP (internet telephony) or via classical PTSN telephony using analog and ISDN.
Practically every communication device available can be used for Unified communication. That includes PCs, Macs, Tablets, IP phones, smart phones and traditional phones, as well as software, used in the UC infrastructure. The software integrated in your UC environment can be anything from an exchange server, a CRM or an ERP system. Unified communication also allows you to send a message on one device, and receive the answer on another device. A good example for this is voicemail. You can receive it on your desk phone, via a soft phone on your smart phone or tablet or via email on your laptop.
UC can take many different forms. It is basically a set of technologies, which can be combined with the purpose of enhancing human communication and increasing efficiency in a distributed environment. UC is especially advantageous for distributed teams with different communication requirements.