But it is not an imaginary device from the future; it is real. And starting today, anyone with a quarter will be able to try out what is being called the nation's first outdoor Internet pay phone, on the southwest corner of Fifth Avenue and West 46th Street.

Whether it will succeed in a city where heavily armored pay phones often become victims of foul play remains to be seen.

The new phone, which allows users to send e-mail, surf the Web and call anywhere in the world for 25 cents per minute, will be unveiled at a ribbon-cutting ceremony at noon, with Public Advocate Betsy Gotbaum and other city officials among the expected guests.

The phone is being installed for a 30-day test run. If it survives, its owner, a TriBeCa-based pay phone company called TCC Teleplex, said it would add 100 more units in the city, mostly in Midtown. TCC has 1,500 conventional pay phones around the city.

There are Internet pay phones at some airports, but today's event represents their open-air debut. Some pay phone owners see the concept as the road to renewal for their struggling industry.

During a trial run at TCC Teleplex's offices, the device was used much like a home computer would be. It includes a traditional telephone handset, as well as a 12-inch screen, black keyboard and square touch pad. It also has a built-in camera, allowing people to take snapshots of themselves and attach them to an e- mail message. There is also a red emergency button with an instant connection to the city's emergency dispatch center.

It may seem foolhardy to add new high-tech street furniture when it is often nearly impossible to find a working pay phone that has not been vandalized or defaced. But the new phone's owners have no illusions about life on the streets: this computer has a steel casing and a thick Lexan shield over the screen. "You can spill coffee or ketchup on it and it will still work," said Dennis Novick, the president of TCC Teleplex. It will be housed in a metal casing, like a pay phone.

The company hopes the new phones will reinvigorate the pay phone industry, which has suffered since the introduction of single-rate cellular phone plans in 1999. Those plans, allowing large amounts of free local calling time, made it cheaper for many people to call by cellphone even when a pay phone is near.

"Roughly 50 percent of American households now have a cellphone," said Vince Sandusky, the president of the American Public Communications Council, a pay phone trade association. That and the new calling plans have helped lead to a drop in the number of pay phones around the country, from 2.6 million in 1998 to about 2 million now, he said.

There are competitors: hand-held Palm-type computers or phones that allow Internet connection, for instance, and Internet cafes. But there are few Internet cafes in Manhattan, and they generally charge more than 25 cents a minute.

The new phones could eventually draw additional revenue from advertising deals with corporations, whose logos could be displayed on the screen or even at the end of an e- mail message, Mr. Novick said. For the moment, the screen shows a revolving sequence of Web sites, including those of the city government, news organizations and the company Broadway.com.

Mr. Novick, who founded TCC Teleplex in 1984, is something of a pay phone buff. He has a wooden pay phone with a crank from the early 20th century in his Hubert Street offices, along with a 1950's three-slot model. "It's a natural evolution in the history of the phone," he said of the new venture