It is an emblem from a bygone era: the outdoor pay phone. For more than a century, in booths along New York City’s sidewalks, public telephones have connected residents, one pocketful of change at a time.

But next month, under a pilot program, some of the phones may be welcoming 21st-century neighbors.

The city’s Department of Information Technology and Telecommunications has approved the installation of as many as 250 “smart screens” in old telephone booths, allowing visitors to find transportation updates, city program information and details about local events, all free.

The touch-screen devices, created by a company called City24/7, will be placed in high-traffic pedestrian areas across the five boroughs, the city said. They will not provide full Internet access.

The department said it planned to find booths with at least two phones and replace one of them with a screen, ensuring that telephones would still be available.