July/August 2005

Technology Trends: Consistent User Input Options and Instructions Across Multiple User Interfaces

By James A. Larson

Many Web developers use XML to represent data and a transformation language, such as XSLT, ASP, or ColdFusion, to transform the XML data to an HTML user interface.  Developers change the values of the XML data without having to manually recode the HTML user interface.

Figure 1. Using a Transformation Processor to
generate multiple user interfaces
Transformation languages can also convert XML data into different user interfaces for access by users with different devices.  As illustrated in Figure 1, developers can use a transformation language to extract and reformat XML data to HTML for publishing on the Web, to Word or PDF for printing, to VoiceXML 2.0 for telephone access, and to a combination of HTML, and either SALT or X+V for multimodal access. 

Suppose a user needs to specify the color of a T-shirt that he or she is ordering.  The developer specifies the color options, instructions for choosing the color, and other explanations once in the XML schema.  The transformation processor then extracts the information and automatically inserts it into each verbal, visual, and multimodal user interface.  Figure 2

Figure 2. Simplified schema containing meta information about the color element

               Which color? for example, blue.
                  We need the color to manufacture the right T-shirt for you






illustrates a simplified XML schema illustrating metadata about the item in an items-for-sale XML file.  Figure 3 summarizes how this metadata can be used in a visual HTML and a verbal VoiceXML user interface.  If you are interested in additional details about this example, see http://www.larson-tech.com/.

Specifying meta information and using mapping languages to construct each user interface has the following advantages: 

By specifying user input options and instructions once and transforming those options and instructions for each user interface, developers minimize manual changes to the user interface and provide consistent user instructions, options, and help messages across multiple user interfaces. 

Figure 3. Use of meta information in visual and verbal user interfaces

Schema element


Use in visual user interface

Use in verbal user interface


Label of pull down menu

Initial verbal prompt

Which color? For example, Blue

(not used in visual user interface)

Secondary prompt if user fails to respond appropriately to verbal prompt

We need the color to manufacture the right T-shirt for your order

Alert message displayed when the user presses the “Why” button

Response when the user speaks “Why?”

Blue, gray, green, and red

Pull down menu choices

Grammar for user response to verbal menu














James A. Larson is manager of advanced human input/out at Intel Corporation and is author of the home study guide and reference VXMLGuide. His Web site is www.larson-tech.com.