Prison-rights groups say making the calls free is fundamentally about fairness. About three quarters of people in the city’s jails have not been convicted of a crime and are there awaiting trial. Regardless of their status, people at the jail are required to pay fees to call family or lawyers on the outside.

Currently, calls from Rikers Island cost 50 cents for the first minute and 5 cents for each additional minute to local numbers. There are 26,000 calls from the city’s jails every day that generate more than $20,000 in daily revenue, according to an analysis by the Corrections Accountability Project, which advocated for the bill. The Department of Correction already provides free phone calls in certain circumstances: Indigent people could make three free phone calls per week, and sentenced inmates could make two per week.

But when the law goes into effect in 270 days, all calls from jail will be free. Securus, the private company that manages phones in the city’s jails, makes about $2.5 million annually. The city will still likely pay a private company that amount.

“People who are incarcerated, and especially people who are incarcerated pretrial without conviction, should be able to contact lifelines without cost,” said Bianca Tylek, the director of the Corrections Accountability Project. She added that the law is a “game-changer” in the country.

The correction officers’ union is not happy about the change.

“Now the gangs will definitely be able to continue to run their operations from inside the jails,” said Elias Husamudeen, the president of the correction officers’ union. “They will definitely be able to continue to communicate free of charge with the other members of their gangs who may not be in jail.