Does SMS messaging keep going when cellular voice is down? [telecom]
Bill Horne
going when cellular voice service is down. Please tell me if this is
true or not.
TIA.
Bill
--
"Where the veterans dream of the fight
Fast asleep at the traffic light"
- Jackson Browne
Ken
>I just read an email that claims cell phone text messaging (SMS) keeps
>going when cellular voice service is down. Please tell me if this is
>true or not.
It depends on what you mean by down. The link between your phone and the
tower is the same for voice and SMS, so if the tower is not operational
due to an extended power loss or the backhaul link broken, then nothing
works.
What's more common is an emergency overload situation. When that
happens, voice calls are blocked or restricted to responder priority
only, but control messages to/from the phone which includes the ability
to send and receive text messages remains available.
danny burstein
>I just read an email that claims cell phone text messaging (SMS) keeps
>going when cellular voice service is down. Please tell me if this is
>true or not.
>TIA.
If the entire cell network (towers, backhaul, etc.) is "down"
for fifty miles around you, you ain't getting through.
If it's up but the voice channels are all in use, then yes,
the SMS should get through.
If the towers near you are down but the one 9 miles away
is working, then it's quite possible you _won't_ be able
to get a voice line through it. But since SMS is "stored",
so to speak, it can stay "on your handset" for fifteen
minutes (number for illustration) until you walk on the
other side of the road and get a short-in-time workable
link to the tower.
(And vice versa for someone sending you something).
--
_____________________________________________________
Knowledge may be power, but communications is the key
dan...@panix.com
[to foil spammers, my address has been double rot-13 encoded]
John C. Fowler
On Tue, 06 Sep 2011 19:34:36 -0400 Bill Horne <bi...@horneQRM.net> wrote:
> I just read an email that claims cell phone text messaging (SMS) keeps
> going when cellular voice service is down. Please tell me if this is
> true or not.
down because the only cell tower in range just got hit by a giant
meteorite, then obviously, your SMS isn't going to work, either. If
you can't get through by voice because some big event is happening and
everyone is trying to call everyone at once, overloading the system,
then SMS could very well get through when voice does not. SMS is
carried at the signalling level and uses much less bandwidth than
voice, so it's easy to prioritize.
If "voice service is down" means "calls start OK but keep getting
dropped quickly", then it's very likely SMS will make it through.
John C. Fowler, johnf...@yahoo.com
Greg Monti
On Tue, 06 Sep 2011 19:34:36 -0400, Bill Horne <bi...@horneQRM.net>
wrote:
> Subject: Does SMS messaging keep going when cellular voice is down? =20
> I just read an email that claims cell phone text messaging (SMS) keeps
> going when cellular voice service is down. Please tell me if this is
> true or not.
When all voice channels are busy (during a crisis) so that it appears
*to you* that the cellular voice network is "down," SMS messaging
continues to work because all users time-share tiny bursts of time on
a data channel. If the SMS channel is busy at the moment you press
Send, your phone places the message into a queue and sends it when the
data channel is not busy. This could be a fraction of a second later,
or ten seconds later, or a minute later. It does not matter to you
since your message did eventually get sent.
If the cell network itself is down, or if all cell towers within
reasonable receiving range of your handset are down simultaneously,
then neither voice nor SMS will work.
Greg Monti, New York, NY
gmo...@mindspring.com
Scott Dorsey
>I just read an email that claims cell phone text messaging (SMS) keeps
>going when cellular voice service is down. Please tell me if this is
>true or not.
If it's down because too many people are trying to make calls in the same
area and clogging up the links between towers, then lower bandwidth SMS
messages are apt to go through even when you cannot get a call through.
If it's down because there's no power to the tower, or a storm blew it over,
or for some other reason the handset cannot get a connection to the tower,
then indeed SMS messages won't go through any more than phone calls.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Joseph Singer
>
> I just read an email that claims cell phone text messaging (SMS) keeps
> going when cellular voice service is down. Please tell me if this is
> true or not.
It's only sort of true. What's really going on here is that if you try to
make voice calls when the network is heavily loaded with people attempting
to make calls your call attempt may fail due to lack of voice circuits to
handle your call. SMS i.e. text messages are more likely to succeed in
being sent and delivered partly because they don't use the voice circuits
or use an infinitesimal amount of the mobile infrastructure to work. Of
course it will only work if the infrastructure to process it is live and
not cut off because either the base station has lost power or the back
hall[sic Mod.] from the base station to the rest of the network has been
damaged.