Although this book doesn't target the development platform that Office Communications Server offers, it's worth pointing out what SDKs are available to developers who want to customize the UC experience or build applications on the UC platform.
The Microsoft Unified Communications AJAX SDK includes documentation and sample applications of the AJAX Service API for cross-platform Unified Communications application development. Use of these APIs is best targeted for Web-based applications. Because it is based on XML, no knowledge of the Session Initiation Protocol (SIP) is necessary.
The Software Development Kit for the Microsoft Unified Communications Managed API version 1.0 (UCMA v1.0) includes documentation of the API, sample applications that use the API, and a redistributable package. UCMA v1.0 is an endpoint API that provides the flexibility and scalability required by advanced developers to build and integrate server applications (for example, alert broadcasting, persistent chat, instant messaging response bots, and so on) into an existing Microsoft Office Communications Server 2007 infrastructure. A working knowledge of the SIP protocol is required to use these APIs.
Microsoft Unified Communications Client SDK provides a powerful and flexible API for building client applications, similar to Office Communicator, for Office Communications Server 2007. The SDK allows application developers to integrate Office Communications Server 2007 enhanced VoIP, Video, Instant Messaging, Conferencing, Telephony, Contact Management, and Presence into their applications. This API offers developers full control over the user interface of their client application. An understanding of the SIP protocol is valuable.
The Microsoft Office Communicator 2007 SDK enables quick integration of Office Communicator 2007 in Windows and Web applications. You can use this SDK to show presence on Web pages and embed communication entry points to Office Communicator 2007 in line-of-business applications. Unlike the Microsoft Unified Communications Client API SDK, use of these APIs will launch Office Communicator UI. No knowledge of SIP is necessary.
The Microsoft Office Communications Server 2007 Software Development Kit (SDK) includes documentation, Microsoft SIP Processing Language (MSSPL), WMI APIs, and sample applications to develop against the Office Communications Server 2007. Extensive knowledge of SIP is required to use these APIs. Plug-ins for Microsoft Office Communications Server that can monitor, archive, and have an affect on the routing of messages through the server are possible. MSSPL supports .NET applications. Examples of applications that can be created are as follows:
Content filters (remove or modify specific words/phrases or types of data)
Custom archiving of messages to specific stores or in specific formats
"Ethical Wall" applications that block specific people from communication (most often because of regulatory requirements)
Data mining, where the contents of the message exchange are used to provide enhanced information to the participants