Overland Park ? Nathan Bales represents a troubling trend for cellular phone carriers.

The Kansas City-area countertop installer recently traded in a number of feature-laden phones for a stripped-down model. He said he didn’t like using them to surf the Internet, rarely took pictures with them and couldn’t stand scrolling through seemingly endless menus to get the functions to work.

“I want a phone that is tough and easy to use,” said Bales, 30. “I don’t want to listen to music with it. I’m not a cyber-savvy guy.”

But the wireless industry needs him to be comfortable with advanced features and actively use them. As the universe of people who want a cell phone and don’t already have one gets smaller, wireless carriers are counting on advanced services to generate the bulk of new revenue in coming years.

Consumers last year paid $8.6 billion for so-called data applications on their phones, up 86 percent from the year before, according to wireless trade group CTIA.

But they’ve also shown a growing frustration with how confusing those added features can be. A J.D. Power & Associates survey last year found consumer satisfaction with their mobile devices has declined since 2003, with some of the largest drops linked to user interface for Internet and e-mail services.

Sprint Nextel corp. researchers Robert Moritz, left, and Clyde Heppner watch a closed-circuit television as a volunteer on the other side of a one-way mirror performs functions on a Sprint cell phone at the company's operational headquarters in Overland Park. The company uses such research to make the phones it sells simpler to use.

That has providers working hard to make their devices easier to use – fewer steps, brighter and less cluttered screens, different pricing strategies – so that consumers will not only use data functions more often but also be encouraged to buy additional ones.

For Sprint Nextel Corp., the process begins in a suite of small rooms on its operations campus in Overland Park.

On one recent day, a trio of researchers watched through one-way glass and overhead cameras as a volunteer navigated her way through a prototype program that lets parents set limits on their children’s phone use.

The observers monitored how many steps it took for the woman to make the program work, how easily she made mistakes and how quickly she could get out of trouble. The results could be used to further tweak the program, said Robert Moritz, director of device development.

“If you bring somebody in and they have problems, it’s not because they’re dumb, but we were dumb with the design,” Moritz said, adding that the lab typically tests devices and programs with up to 50 users over three to nine months.

So far, Sprint Nextel is doing something right, as its subscribers spend the highest average amount for data services in the industry.

The other major wireless providers use similar techniques to improve their devices and programs.

Cingular Wireless, the nation’s largest wireless provider, developed MEdia Net, which allows users to personalize their phones for using the Internet, downloading ringtones or getting e-mail.

Verizon Wireless has V-Cast, a service that makes it easier to download music and video. The company also has pushed designs that allow users to accomplish many things with one button press.

T-Mobile also has focused on a few key areas, introducing T-Zone to help customers find ringtones and screen wallpaper by subject and decreasing the number of steps to take and send photos, for example.