GATINEAU, Que. -- The CRTC says wireless carriers must make changes to their networks and systems to support 911 emergency text messages for hearing or speech-impaired persons within 12 months.

The service would only be provided to the hearing or speech-impaired who have pre-registered for it with their wireless carrier.

Once registered, they would be able to call 911 in the traditional way on their cellphones, but the call would be flagged as coming from a pre-registered person with a hearing or speech impairment.

The CRTC says the 911 operator would respond by sending a text message to the caller, and the caller and 911 operator would continue to communicate back and forth via text messages.

The regulator also requests that carriers have a plan to inform these subscribers and the general public of the 911 text messaging service for the hearing or speech impaired.

The Canadian Radio-television and Telecommunications Commission has been asking Canadians, especially emergency responders, for ideas on how to improve 911 service in light of changing technology.