Wagner said Census Bureau officials didn't specify the use of Windows Mobile 5.0. The bureau's request for proposals listed general functional requirements, including usability and reliability levels, instead of setting any technology mandates. "It didn't matter to us if it was Windows Mobile 5.0 or something else," Wagner said. "It was up to [the vendors] to figure out the right solution."

The team led by Harris was chosen after a demonstration of handheld prototypes by all the bidders in January, he added. The prototypes had to include mapping support, an application for updating the addresses of residents, and a time-and-expense form for use by census workers.

Buckley said Harris chose Windows Mobile 5.0 for the handhelds primarily because the Microsoft operating system can run customized versions of off-the-shelf applications that the Melbourne, Fla.-based systems integrator has experience with. That includes software for security and wireless data synchronization.

All data collected by census takers will be transmitted over the Sprint Nextel network immediately or at set intervals, according to Buckley. If workers fail to send data as scheduled, the handhelds will do so on their own, he said. In addition, the Census Bureau will be able to send information to workers, such as advisories notifying them that residents on their routes have already filed paper-based census surveys and can be skipped.

Buckley said there will be no keyboard on the handhelds; instead, data will be input primarily by tapping a stylus on a color screen. The handhelds also aren't expected to have voice capabilities, a decision made to comply with government security requirements and keep costs low, he said.