Unified communications (UC) is the integration of real-time communication services; instant messaging, presence information, telephony, video conferencing, call control and speech recognition with non-real-time communication services such as unified messaging (integrated voicemail, e-mail, SMS and FAX).
UC also refers to a means of business process integration, simplifying access from all forms of communication media and reducing device and media dependencies. UC allows an individual to send a message on one medium and receive the same communication on another medium. For example, one can receive a voicemail message and choose to access it through e-mail or a cell phone. If the sender is online according to the presence information and accepts calls, the response can be sent immediately through text or video call.