Many standard office environments have workspaces that contain a computer running a Microsoft operating system with Microsoft Office, and a Private Branch eXchange (PBX) phone. Typical information workers perform their daily work using this standard technology. In daily workflow, calls are placed to phone numbers of contacts whose contact information is located in Microsoft Office Outlook or the Global Address List, based on data stored by Microsoft Active Directory Domain Services. Without the ability to place a phone call directly from the desktop computer, the user must manually enter a phone number on the desktop phone while looking at the screen and typing the digits. This is not only inconvenient but also can result in calls placed to the wrong destination.

The Remote Call Control (RCC) scenario for Microsoft Office Communications Server 2007 R2 eliminates the necessity of manually entering phone numbers stored on the computer into a PBX phone. Furthermore, a user’s Microsoft Office Communicator presence state will reflect the fact that she is in a call by changing the presence state to "in a call" status. This scenario is supported by Microsoft Office Live Communications Server 2005 Service Pack 1 (SP1) and by Office Communications Server 2007 R2 with Office Communicator 2007 R2. Integration between Office Communicator 2007 R2 and Office Communicator Phone Edition 2007 R2 also provides RCC-like features. This aspect is covered later on in Chapter 11.

The user enabled for RCC can control her PBX phone through the Office Communicator 2007 R2 graphical user interface (GUI). If the company has the Office Communications Server 2007 R2 Edge Server deployed to allow Remote Access scenarios, it is even possible for the user to control her office desktop phone while she is connected remotely from the Internet. For example, a user can receive an incoming call on her PBX extension in the office and deflect the incoming call to her mobile phone by clicking the pop-up alert toast that indicates the incoming call on Office Communicator 2007 R2.

In the RCC scenario, the voice media stream of a phone call stays on the existing PBX phone and is not handled by Office Communicator 2007 R2. This is one of the major differences between the RCC scenario and the Enterprise Voice scenarios, as described in Chapter 11.

On the Companion Media

See this book’s companion CD for resources related to this chapter.

A Remote Call Control Scenario

As shown in Figure 9-1, a user using the RCC scenario has a PBX phone with a desktop computer running Office Communicator 2007 enabled for RCC.

Figure 9-1. System architecture diagram for RCC scenario

Apart from enabling the user’s Office Communicator 2007 R2 for RCC, it is necessary to install at least one Session Initiation Protocol/Computer-Supported Telephony Applications (SIP/CSTA) gateway connected on the existing PBX that hosts the user’s PBX phone. CSTA is an international standard set by the European Computer Manufacturers Association (ECMA) to combine network servers with PBX environments.

There are PBX-specific SIP/CSTA gateways and vendor-neutral SIP/CSTA gateways, such as Genesys Enterprise Telephony Software (GETS) from Genesys, and it is the task of these gateways to transmit call-related signaling information from the PBX to Office Communicator 2007 R2 and vice versa. The SIP/CSTA gateway does this by establishing and terminating SIP sessions on the IP network site and converting CSTA commands received on the SIP network to these signaling messages understood by the PBX. CSTA does not handle the voice media stream of the call, only the signaling aspects of the call.