When many 911 calls weren’t going through late last month due to an outage at a Louisiana telecomm giant, vintage technology helped save the day in Boston.

After a fire broke out in a building in the North End early on Dec. 21, a resident who couldn’t use a cellphone because of the outage pulled the firebox on the street outside. And soon, a fire crew was on the scene.

In Boston, there are more than 1,000 fireboxes, a system invented in the mid- 19th century that works even when modern technology doesn’t. Tell anyone that that’s the case, and they may not believe you.

“There’s no way it works. I’ve been told for the past 20 years that they don’t work,” said Mark Contrado, who lives near the scene of Friday’s North End fire. “After you pull it, you talk to them or what?” he asked of the box at the corner of Cooper and Endicott streets.

At the Boston Fire Museum, Michael Gerry shows off a vintage fire box. “Pull the handle down on the fire box,” he instructs. “And there’s a white button there .... and you push the white button down and you can hear what happens.”

These alarm boxes were invented in Boston and have been around since the 1850s. Back then, they’d set off a bell. Nowadays, it’s a computer display. Whether or not fire boxes are activated, Gerry says, they’re used every day by the Boston Fire Department.

“Each city address is cross referenced to a fire box like a zip code,” he says. “And that fire box number is then back transmitted out to the stations.”

The boxes let the fire department know which engine needs to respond. A computerized voice announces the call: “Engine 17. Ladder 7. A motor vehicle accident. 124 Pleasant Street. Dorchester. Nearest Box: 1864 Pleasant and Roche Street.”

“They gave the nearest box location,” Gerry says. “1864 Pleasant and Roche. So, the companies going to that incident will use a specific route to go from the fire house to go into that location.”

Back at the box in the North End, Contrado, who was skeptical about them working, is impressed. “You would expect them to not work, because of how old they are,” he says. “But, I do think that they should work.”

And for the foreseeable future, the fire boxes around Boston will remain in operation, should you ever need one.

Quincy Walters is a reporter for WBUR 90.9FM, Boston’s NPR News Station. The Reporter and WBUR have a partnership in which the two news organizations share content.