Phone Integration Architecture

Communications Server can coexist with conventional phone equipment and networks. Shown here is the architecture of a typical system in which every voice user can employ either Communicator or a conventional phone connected to a private branch exchange (PBX), which in turn is connected to the public telephone network. The user can place calls with either Communicator or the phone; incoming calls ring both Communicator and the phone, and the user can answer at either endpoint.

Two elements (shown at bottom) support this coordination:

• A media gateway from a Microsoft partner translates between the PBX telephony interfaces and the protocols used by Microsoft’s unified communications products
• Mediation server, a Communications Server component, implements Communications Server features that can’t be handled by the media gateway; for example, it can convert call audio between the RTAudio format used internally by Communications Server and the G.711 format used by many gateways.

The two elements can be combined into a single device to simplify management. For example, partners are developing “basic hybrid” media gateways that run the Mediation component and gateway components on the same hardware. Microsoft partners are also developing “advanced” media gateways that incorporate Communications Server support directly, eliminating the need for Mediation server. Finally, some partners are developing “unified communications-enabled” PBXs that directly incorporate support for Communications Server, eliminating the need for a gateway.