I've done some work in this area. We enable the caller to text but all of the data transmission done over the voice channel. This allows for locating the call, a live conversation and it could be made compatible with all 911 centers.
About time.
Many people's lives have been saved by being able to send a text to a friend from somewhere in the backcountry / offshore where they couldn't make a call but there was enough signal for a txt.
[+] [-] nirmal|16 years ago|reply
Our users are deaf but anyone could use this.
See http://nirmalpatel.com/research/deaf911.html
[+] [-] ergbvreg|16 years ago|reply
[+] [-] elliottkember|16 years ago|reply
[+] [-] kingsley_20|16 years ago|reply