Mayor John DeStefano Jr. placed tens of thousands of telephone calls in a matter of minutes Monday afternoon as he broadcasted the first official city-wide voice message to New Haven land-line phones using a recently purchased mass-notification system.

In a message to New Haven households, the mayor relayed information about a new Connecticut Department of Transportation initiative that provides free bus passes valid for 10 rides on CTTRANSIT local and commuter buses. A report on the number of messages that were successfully delivered is not yet available, City Hall spokeswoman Jessica Mayorga said.

According to a City Hall press release, the system is capable of contacting an average of 29,390 homes — roughly 60 percent of city households — within 20 minutes.

City administrators who are authorized to use the system can target messages to the entire community, or even a segment of a single street.

The system’s primary purpose is for emergency notification, but because the city pays for the notification service on a per-year — not per-use — basis, the city also plans to use the system to notify residents of important events.

“Still, the first and most important use of this system is for emergency notification,” Mayorga said.

The system, which is powered by the company 3n — National Notification Network — costs $56,000, or 45 cents per person under the city’s current contract, according to the press release.

The Department of Homeland Security is funding the cost of the system, Mayorga said.

New Haven previously conducted two smaller-scale tests of the notification system, according to the statement. On Nov. 1, a message was broadcast about the leaves pickup schedule. And Nov. 9, another message was delivered to inform residents of bridge closures.

Most Yale numbers are not listed in the New Haven White Pages, the source for phone numbers used by the notification system. A Yale Telecom employee said the Yale Office of the Secretary has discretion over which Yale offices and administrators have their numbers listed in the White Pages.

Earlier this month, the University Secretary’s Office tested its new Yale ALERT emergency notification system by e-mailing, calling and sending text messages to University students and affiliates. The University previously used a land-line phone alert system.