Cell Phones - Texting Ability When No Call Possible

I saw a blip on the news about Chicago having a testing the ability to text to 911.

Evidently there have been times when people needed emergency services but could not dial out on their cell phones. However these people were able to text to their friends and have the friends call 911 and relay the emergency.

My question is, how come, in some cases is this possible? I thinking that texting just takes of the spectrum?

I can text without worrying about dropped calls. It’s rare that I get a failed sent message error.

I would assume that in some situations you don’t WANT people to know you are calling 911. And if you happen to be deaf or hard of hearing, certain services may be out of the question. The deaf people that I know hate tty and prefer a videorelay service, but then you could get stuck in a bad situation. Videorelay is available on some phones, but really, if you’re deaf and in an emergency all bloodied and stuck on an abandoned county road…wouldn’t texting be beneficial?

The FCC is currently conducing a survey on the issue right here: http://www.fcc.gov/cgb/dro/EAAC/

Cell phones send all their calls and texts out digitally these days. Texting uses the same part of the spectrum but much less bandwidth, requiring a much less solid connection. Think of it as the difference between screaming “HELP!” and screaming a passage from Shakespeare; in a digitally noisy environment, there’s just too much else going on for the latter to transmit clearly.

It also helps that in some network configurations, text messages piggyback on a part of the transmission protocol that can still go through when the network’s overcrowded with voice calls.

Sometimes when I don’t have a signal, I’ll send a text, and it will go through sometime later.

Text messages can be auto-retried from the phone if you have spotty network coverage. If you get a short blip of service, the phone will send the text.

In this scenario, you probably wouldn’t be able to place a phone call…and if you actually placed it in that short window, it would drop when the service drops.