Read these conceptual, overview topics for the background knowledge that you need to build an intelligent plan.
•
Cisco Unified Communications System Description 
This document contains a high-level overview of the Cisco Unified Communications family of products.
Links to other key topics:
•Determine Your Business Requirements
•Understand Your Deployment Options
Cisco Unified Communications System Description
The Cisco Unified Communications System Description document is a high-level overview of the Cisco Unified Communications system approach, in which individual Cisco hardware and software components are integrated for seamless interoperability. Download the complete PDF version of the Cisco Unified Communications System Description (right-click to download PDF), or view these topics:
•Cisco Unified Communications Component Overviews