FCC is requiring text-to-911 on all carriers, though most 911 centers can’t receive them

The Federal Communications Commission voted 3-2 to require all mobile carriers to route text messages sent to 911 to local emergency response centers — just like phone calls — by the end of the year. The decision might not have much of an impact though.

The big four operators have already implemented text-to-911 voluntarily, though many smaller operators have not. But the big issues is that only about 2 percent of 911 response centers are capable of receiving SMS, so most emergency messages just get sent into the ether (though carriers are required to notify such texters that their messages weren’t received).

By codifying the rules, however, emergency responders may be more inclined to implement the technology. The FCC said that two entire states, Maine and Vermont, are already fully equipped to accept emergency texts, and about 100 total call centers in 16 states have SMS capabilities.

The FCC also now requires over-the-top messaging apps linked to phone numbers must all support 911. That means an app that works within the phone’s SMS client such as iMessage(s aapl) must be able to send 911 texts, but a social messaging app like Facebook Messenger(s fb) or WhatsApp does not.