Leveraging Web infrastructure for speech applications. (Call Center/CRM Management Scope).

VoiceXML is a language designed for writing speech-based applications, As HTML is designed to interact via a computer, VoiceXML is designed to interact via a telephone, and its solutions use many of the same architectural components as HTML.

From a functional perspective, it is helpful to imagine a VoiceXML platform as conceptually similar to an IVR system, only much more flexible. VoiceXML plat-forms use open standards and are designed to be interoperable with components from multiple vendors. As a result, these platforms make it easier to deploy voice-based solutions.

The term "VoiceXML platform" refers to the collection of telephony interface, speech recognition, text-to-speech synthesis and VoiceXML interpreter software necessary to actually process a call. The VoiceXML interpreter takes a VoiceXML script and uses it to guide the caller's interaction with the system. The platform then retrieves these scripts using HTTP, the same protocol Web browsers use to access HTML pages.

The result is that the architecture of a voice system using VoiceXML looks very similar to that of an HTML-based solution. There is a Web server that responds to the HTTP requests. The Web server interfaces with an application server that runs the business logic and creates dynamic content. The application server, in turn, will "talk" to the back-end system containing the customer information. The major difference occurs on the side closest to the user. A customer accessing the HTML interface uses a browser to view data from the Web server. By contrast, a voice caller calls the VoiceXML platform over the telephone, and that call causes the platform to speak those data from the Web server, The platform "listens" to the user's responses and interacts appropriately with the Web server.

VoiceXML platforms are currently appealing as they are usually more cost-effective than proprietary IVR platforms. The cost per telephony port for the actual equipment is typically lower for VoiceXML platforms, Also, because VoiceXML is a standard language, it rends to be easier to find developers. This is in sharp contrast to proprietary systems, for which the only practical source of development is the vendor's own professional services department. The breadth of adoption of the language also means that there is a variety of tools available to aid with content creation, which saves production time. The biggest source of cost savings, though, comes from the ability to reuse existing Web infrastructure.

There are four major components of creating a voice solution. The first is the design of the voice interface, deciding what both the system and the user will say at each point of the interaction. Then comes the production phase, in which the various prompts, scripts and grammars are created. The back-end integration work is the next major piece of work, and will typically be done concurrently with the production. Last is the ongoing maintenance, in which grammars are tuned, capacity is monitored and incremental script improvements are made.

The biggest cost sayings comes in the backend integration work, due to the fact that VoiceXML scripts are served from standard Web servers. Because the platform retrieves these scripts using HTTP, many of the tools and components that have been developed to allow access to back-end systems from HTML pages can be used for VoiceXML as well. integration with back-end systems often consumes a very large portion of a total implementation effort, since it is often very unique to each implementation. However, if this back-end work has already been done for HTML pages, then implementing similar voice functionality may require no additional integration work.

A good example is an order tracking system. A company might have an HTML-based system that allows a customer, via a Web browser, to query whether or not an order has shipped. Typically, an application server will dynamically create the HTML and deliver it via a Web server. The code running on the application server will, in turn, need to communicate with a legacy system to retrieve the order information.

An IVR system attempting to replicate this functionality would typically not be able to use the Web application server, and therefore nor be able to leverage the code that was written to support the HTML system. Providing callers with functionality equivalent to that enjoyed by those using HTML browsers would likely require integrating from scratch, probably involving the vendor's professional services department.

This is where the value of VoiceXML really shines. The voice application can run on the same application server and use exactly the same code to access the legacy system. This not only minimizes development, but also ongoing maintenance. The possibility for reuse of the same application servers also reduces the need for engineering training and can reduce software licensing costs.

VoiceXML can make the ongoing maintenance of a voice solution easier, as well. Monitoring of the load on rhe Web and application servers can be done with the same tools the IT department is already using for the HTML solution. In fact, depending on the network design, the same physical systems can potentially be used for both the HTML and voice solutions, allowing the computing resources to be shared between them, In a properly configured load-balancing cluster, this approach can allow the two solutions to run with less total server hardware than if they were separate, especially if the peak loads for the two systems occur at different times of the day.

Creating a voice solution is still a major undertaking. The design of the voice interface and the grammars to support interpretation of the users' speech requires a great deal of effort by experienced specialists. VoiceXML platforms, while cheaper than IVR platforms, still represent a significant investment. However, a well-designed system can divert a large percentage of calls away from live operators to self-service. Recovery of the system cost can often occur in under a year. These factors, coupled with the reuse of the Web infrastructure, create very attractive economics and are a large part of the reason for the tremendous success of VoiceXML as a technology for voice solutions.

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Jim Seidman is vice president of engineering for Verascope, Inc. He has worked on developing the standards for several Internet technologies, including HTML, HTTP, WAP and VoiceXML. Verascape isa provider of integrated VoiceXML platforms.