The Federal Communications Commission voted on Friday to require all of the U.S.’s cell phone carriers and popular messaging applications to allow users to text 911 to emergency response units.

Since 2012, customers using any one of the four largest carriers in the country — AT&T, Verizon, Sprint and T-Mobile — have been able use text-to-911 service, following a voluntary agreement between the companies and the FCC. However, today’s 3-2 vote will require smaller, regional carriers to follow suit by the end of the year.

“Texting is now as important a function on a mobile device as talking. Some of those text messages are cries for help,” FCC Chairman Tom Wheeler said. “Some of those are from people who can’t hear or speak. Call 911 if you can. But if you can’t, what are you going to do?”

The requirement seeks to address the changing ways in which people are communicating, and is not without significant hurdles. According to the FCC, more than 70 percent of attempts to get in contact with emergency services originate from cell phones while only two percent of emergency responders nationwide are currently equipped to accept the messaging.

“In your moment of need, if you try to reach 911, you won’t reach it no matter what application you use,” warned Republican FCC Commissioner Ajit Pai, who voted against the regulation. “Nothing in this order will change that fact any time soon.”

Additionally, unlike cell phone calls, it is difficult to determine the exact physical origin of a text message, particularly in residences with multiple floors.

The FCC’s new rule comes at a time when cell phone users are increasingly using third-party messaging apps like Google Voice, iMessage and WhatsApp that provide SMS-like services that are handled via Internet protocol. As of Friday, the FCC will require all third-party applications that interconnect with the traditional SMS infrastructure to comply with its rules, but it expressed its intent to reach out to developers to make text-to-911 universal.

“Our first responsibility is to provide for the safety of Americans,” Wheeler said, following the vote. “This is a step to continue to fulfill that responsibility. And it is not a final step.”