The standard architecture for multi-channel phone applications today consists of the following:

• Unified service creation environment based on the Eclipse framework
• Unified service execution environment based on a phone application server
• Unified back-end infrastructure based on a service-oriented architecture (SOA)

In the remainder of this article we'll focus on the service creation environment to see how it helps developers create a better experience for callers.

Eclipse Framework
Eclipse provides an open framework to combine best-of-breed tools into a powerful integrated workbench. Instead of having to make compromises when selecting a monolithic IDE, developers can pick and choose what suits them best from a wide variety of open source and commercial components. Acting as plug-ins in the Eclipse architecture, these components blend into the overall workbench and smoothly interact with each other.

The benefits of this approach are particularly strong when building multi-channel phone applications, since dedicated tools can be used for the specific technical needs of the different channels. Even better, many of these tools are available as free downloads such as the ones we take a closer look at here.

A good example of a comprehensive multi-channel framework is VoiceObjects Developer Edition, which provides integrated support for the voice, video, text, and Web channels (see Figure 3). Included are a graphical IDE as well as an embedded phone application server for one-click testing and deployment. Applications are built using an object-oriented approach on the basis of a set of core components modeling caller interactions as well as back-end integration and application logic. Rapid prototyping and object reuse are facilitated by a drag-and-drop GUI.

Adaptive personalization is achieved through the concept of "layers," which also covers topics such as multi-lingual or multi-persona applications. Integrated testing and debugging is available for all phone channels, including a phone simulator that shows text and Web applications as they would look on a variety of mobile handsets. To test voice applications end-to-end, complete software IVRs such as Voxeo's Prophecy can be downloaded or hosted IVRs such as Tellme can be used.

If you're focusing purely on the voice channel, there's the Eclipse Voice Tools Project. Applications are designed from a basic set of configurable building blocks using the box-and-arrows approach, similar to Microsoft Visio. Application logic is defined through custom JavaScript code. For testing, applications can be packaged into WAR files and manually deployed on a choice of Web application servers such as Tomcat.

Grammars are an important aspect of voice application development. Things a caller might say such as "There's a problem with my bill" or "Transfer five hundred dollars" must be modeled so that the speech recognition engine can successfully understand them. Nu Echo's NuGram IDE offers a suite of tools to manage these grammars efficiently. Productivity features such as auto-completion and on-the-fly validation assist in building grammar rules. For testing and tuning, sample caller utterances can be parsed to analyze grammar coverage and ensure correct semantic interpretation (see Figure 4).

Access to back-end systems is a crucial part of development regardless of the channels served by an application. Within the Eclipse eco-system, several frameworks are available to help with this task. Two important ones are the Web Tools Platform (WTP) and the SOA Tools Platform (STP).

For simple or one-off tasks, JavaServer Pages (JSPs) are often the solution of choice because of their low overhead and straightforward integration of static and dynamic content. The WTP offers a rich set of features to support their development, testing, and deployment.

For more complex and reusable tasks, Web Services are the preferred way to go. The STP provides a broad scope of capabilities covering SOA aspects from business process modeling and service orchestration to code generation, deployment, testing, and documentation.

The Eclipse plug-ins highlighted here are just a selection from among the large set of freely available tools. The ever-growing number of open source projects and commercial contributions is a strong indicator of the dominant position the Eclipse platform has achieved in the developer community.

Apart from being excellent tools in their own right, the added benefit when using plug-ins like the ones listed above together in the Eclipse workbench is the smooth interoperability: You can check and tweak a speech-recognition grammar while looking at the dialog flow that reacts to the corresponding caller input. You can adjust the application logic with simple drag-and-drops while building the Web Service code that connects to the back-end. For the first time, developers have simultaneous control of all application aspects without needing to switch between IDEs or compromise on features when selecting a single environment.

Summary
Mobile applications are here to stay.

Users have come to depend on retrieving information and performing transactions on-the-go. And they expect the same level of convenience and efficiency they know from home - regardless of whether they call an 800 number, send a text message, or visit a mobile Web site. The challenge lies with the developers to deliver multi-channel phone applications that adapt dynamically to each caller's needs and expectations.

The merging of IVR and Internet technologies has made it possible to apply the lessons learned on the Web to all phone channels: Benefit from a scalable multi-tier architecture centered on an application server. Unify back-end access through the use of Web Services and SOA.

On the IDE side, the Eclipse framework has provided the fertile ground on which a multitude of interoperable plug-ins has sprung up that presents developers with a comprehensive suite of capabilities. Every aspect of multi-channel application development can be addressed - and not in isolation, but in correspondence and coordination with each other.

Just as important, most of these Eclipse plug-ins can be downloaded for free, giving developers a choice and allowing them to evaluate each tool's respective benefits.

Never before has it been easier to get from idea to implementation. The flexible and scalable infrastructure is in place, and the tools to realize innovation are in the developers' hands.

The time for better phone applications has finally come.

Resources

• VoiceObjects Desktop for Eclipse: A comprehensive framework for building multi-channel phone applications.
• Nu Echo NuGram IDE: A professional tool set for efficient grammar development.
• Voxeo Prophecy: A software IVR complete with speech recognition and text-to-speech engines, ideal for end-to-end testing.
• Tellme: A hosted IVR.
• Eclipse Voice Tools Project: A basic voice application development toolset.
• Eclipse Web Tools Platform: A set of tools for development and testing of JSPs and other Web-related code.
• Eclipse SOA Tools Platform: A tool suite for business process modeling and Web Services.
• W3C mobile application best practices: Valuable design guidelines for mobile applications: often, less is more.