Early Adopter VoiceXML

System Architecture

The figure on the left is a block diagram showing the existing components of the system, and the relationships to the new XML/XSLT system required to implement the voice interface.

This drawing is not complete in all areas. For example, no method for user login and authentication is given, because such a system would already exist for an e-commerce site, and because although XML/XSLT would be helpful for creating device-specific login code, we are not going to examine on- the-fly transformation (inside a web server, for example) in this particular study.

Designing a Voice Interface

With these rather vague requirements in mind, we can make some design decisions, and sketch out a rough model for the voice interactivity envisaged. The goal is to make the experience simple and intuitive.

• There will be a main menu of options. This is the entry point to the application, and the user can always return to it with a single voice command.
• Online help will always be available. This will use the VoiceXML <help> tag to simplify implementation, and also to overload any built-in help that may be offered by the voice platform.
• The number of available options from the main menu should be kept to a minimum. The total number of states should also be minimized. This means that the behavior of the current command should not depend on what the previous command issued was. For example, the word "menu" should always refer to the main menu in every context.
• The top-level commands from the main menu should always be active. If the main menu offers the command "foo", the user should be able to say "foo" at any point in later dialogs with the same result.

The following state diagram illustrates these design goals. The main options are "order status", "product list" (with a link to voice ordering via the existing phone service bureau), and "more information" to access a frequently asked questions list. For a more detailed examination of the issues to consider when designing voice applications, refer to Chapter 6. The order status menu leads to a variable number of additional choices, depending on the number of records in the user's order history.

Early Adopter VoiceXML - Sample Chapter 7

• Part One
  • VoiceXML with XSLT (HTML and WML)
  • System Architecture
• Part Two
  • Creating a Markup Language - Coming Soon
• Part Three
  • VoiceXML Stylesheet - Coming Soon

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