Dozens of law enforcement and fire agencies in Los Angeles County can now receive SMS text messages to 911.

The capability announced Friday is aimed at mobile users who are hearing and speech impaired as well as those who may be in a situation where it is too dangerous to dial 911.

A voice call is preferred, so the technology is being deployed along with the slogan, “Call if you can, text if you can’t.”

Authorities say an example of a situation where someone may not be able to communicate verbally is a victim of domestic violence who is hiding from an abuser.

Potential users of text-to-911 should familiarize themselves with technical limitations, such as unavailability when roaming. Messages also must avoid using popular abbreviations and emojis.

We appreciate the enthusiasm, but please don’t send “testing,” or “just making sure this works” text messages to 9-1-1. The system is working and these messages prevent operators from handing other calls. Text-to-911 is for emergencies only. Thank you. @LAPDHQ #TextTo911 #LAPD

— LAPD Communications Division (@911LAPD) December 2, 2017

Here are two back-to-back examples of “testing” messages we received on Text-to-911 last night… pic.twitter.com/AqchHwsQan

— LAPD Communications Division (@911LAPD) December 3, 2017

(AP)