Because Unified Messaging must be integrated into your company's telephony solution, it's important to understand the most crucial terms and definitions to be able to follow the discussions in this chapter.
If your company is already connected to Office Communications Server 2007 or later with your telephone system, you don't need to consider the details in the following sections; Exchange 2010 will use OCS as the gateway.
Three general types of business telephone systems can be integrated with Unified Messaging:
Centrex Phone System Phone companies lease a Centrex phone system (also known as Central Office Telephone Exchange) to businesses. The Centrex phone system uses the phone company's central ...