Text-to-9-1-1

Text-to-911 is a technology that enables emergency call takers to receive text messages. Its use is encouraged for the hearing impaired and in situations when it is too dangerous to call. As of May 2014, all four major carriers in the United States offered text-to-911. However, as of October 2018, only approximately 1,600 of more than 6,000 emergency call centers were setup to receive texts.
Adoption.
The FCC maintains a registry of areas supporting text-to-911. All carriers are required to send bounce-back messages to inform the sender that the message could not be received if text-to-911 is not supported by the local call center.