Standard Edition provides all IM, presence, and conferencing components, including data storage, on a single computer. Standard Edition call features include the following:

• Basic computer-to-computer calling: Place, accept, hold, retrieve, and end calls.
  
  
• Able to accept conference invites, but unable to set up conferences.
  
  

Because a Standard Edition server represents a single point of failure, we do not recommend it for mission-critical deployments where high availability is essential. For such deployments, Enterprise Edition is the required choice.

The architecture of Office Communications Server 2007 R2 Enterprise Edition reduces single points of failure through the use of multiple Enterprise Edition servers and a dedicated Back-End Database server. Enterprise Edition call features include the following:

• All Standard Edition call features.
  
  
• Advanced call features: transfer, deflect, and forward calls.
  
  
• Support for telephony device.
  
  
• Permits scheduling and initiation of multi-party conferences.
  
  

Remote call control (RCC), first made available as a part of Live Communications Server 2005, continues to be supported with Office Communications Server 2007 R2. RCC allows Office Communicator 2007 R2 to control a user's PBX phone line and indicate their presence based on the status of their phone. Users can answer their PBX phone with Office Communicator 2007 R2 and update their presence to "In a Call."

The following table summarizes these settings. For more information about Group Policy, see Group Policy for Unified Communications Clients. For more information about meeting policies, see Configuring Meeting Policiesin the Administering Office Communications Server 2007 R2 documentation.

Group Policies for telephony

* Using the Office Communications Server 2007 R2 Administrative Tools snap-in

The following table summarizes the set of functions for each telephony mode.

Function based on Group Policy telephony mode

*When RCC is not present