Soon anyone with the latest cell phone will be able to check Grandpa's heart monitor, seek a diagnosis of that rattle under the hood, or make sure the hot tub is hot enough. That's because phones now coming onto the market can plug into sensing devices-from health monitors to automotive diagnostic units-to run software that reconciles a hodgepodge of data formats and translates the data for uploading onto wireless networks and the Web.

"The phone is becoming what I call a digital Swiss Army knife,'" says Tony Hillman, a technology manager at Sun Microsystems, which has developed one of the software standards turning up in the new phones. "By downloading different applications you can transform [your phone] into a different kind of device," he says.

VTTi of Moss Beach, CA, is one of the first U.S. software companies to cast phones as wireless data gatherers. The company recently used Sun's Java software, for example, to develop a remote automotive-diagnostics program. A Motorola phone running the program can be plugged into the diagnostics port under the dashboard of most cars, says VTTi vice president of engineering, Tim Clark. The phone converts engine data into packets that can be uploaded to a wireless data network operated by Nextel. The data then go to a central Web server where other Java software turns the information into a Web page that can be viewed by mechanics back at the garage.

Future versions of the VTTi system will work with other phones and with networks being built by other wireless providers, Clark says. On the home front, spa owners can use a similar program to check their tubs' water temperature and chemistry data, and they can also send the data to a Web page where they or technicians can turn up the heat or start the whirlpool jets.