Using Cingular & T-mobile in Florida

I have a tri-band phone (6230i) and last time I was in Florida I had
trouble using a Cingular sim and I had to use a T-mobile sim instead.

The Cingular sim would make calls but not receive them, however it
worked fine in a quad-band phone. I guessed they were using part of
the 850mhz (?) band for controlling calls on the 1900mhz band.

Now I see Vodafone Uk are showing on their website that you only need
a tri-band phone to use Cingular in Florida. Is this right? I think it
might be a mistake.

Jules

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› See More: Using Cingular & T-mobile in Florida

While I was dreaming about my next Hawaii visit <j5lc649ong84itr8u4hukt
[email protected]>, Jules <[email protected]> wrote
>I have a tri-band phone (6230i) and last time I was in Florida I had
>trouble using a Cingular sim and I had to use a T-mobile sim instead.
>
>The Cingular sim would make calls but not receive them, however it
>worked fine in a quad-band phone. I guessed they were using part of
>the 850mhz (?) band for controlling calls on the 1900mhz band.
>
>Now I see Vodafone Uk are showing on their website that you only need
>a tri-band phone to use Cingular in Florida. Is this right? I think it
>might be a mistake.
>
>Jules

-=--=

A friend of mine just got back from Florida (month ago) and he borrowed
my Cingular sim.
Using a tri-band phone he didn't get a signal all week!

Depend where you are I suppose?

Bob.

On Sat, 28 Jun 2008 16:39:59 +0100, Steve <[email protected]> wrote:


>GSMworld.com shows that in the USA, Cingular (now owned by, and
>branded, AT&T of course) operates both 850 and 1900 GSM (2G) networks.
>The coverage in Florida looks fine on both. So you should have been
>OK.

Yes, but my point is that I think the Cingular system uses BOTH 850
and 1900 at the same time to make a call so you can't use tri-band. it
certainly would explain why I had full signal but couldn't receive
calls - only make them.

I was in orlando BTW.

Jules

>On Sat, 28 Jun 2008 16:16:48 +0100, Jules <[email protected]> wrote:
>
>>I have a tri-band phone (6230i) and last time I was in Florida I had
>>trouble using a Cingular sim and I had to use a T-mobile sim instead.

Just found this at:

http://wiki.howardforums.com/index.p...z)_on_Cingular

"If your area is one where Cingular is strictly 1900 MHz, you will
have no issues using a GSM phone with just 1900 MHz. If your area is
strictly 850 MHz, a GSM phone with 850 MHz is required. In dual band
markets, a phone including 850 MHz may be required, or may not be.
This depends on whether the Control Channels are running on 850 MHz.
The control channels keep you connected to Cingular while not using
your phone. If Cingular has Control Channels only at 850 MHz in dual
band markets, a 1900 MHz phone will get No Service, as it can not
access the 850 MHz Control Channel, even though Cingular is running
service at 1900 MHz!! "

Looks like you do need a quad band phone to use Cingular and the
Vodafone site is indeed wrong.

Jules

On 2008-06-28, Jules <[email protected]> wrote:
> I have a tri-band phone (6230i) and last time I was in Florida I had
> trouble using a Cingular sim and I had to use a T-mobile sim instead.
>
> The Cingular sim would make calls but not receive them, however it
> worked fine in a quad-band phone. I guessed they were using part of
> the 850mhz (?) band for controlling calls on the 1900mhz band.
>
> Now I see Vodafone Uk are showing on their website that you only need
> a tri-band phone to use Cingular in Florida. Is this right? I think it
> might be a mistake.

Vodafone is wrong. On much of the east coast of Floria AT&T
owns both of the 850 MHz band allocations, and neither has
nor needs 1900 MHz spectrum. A tri-band phone won't work there.
In other parts of Florida AT&T may have both 850 MHz and
1900 MHz allocations, but in places where they have both
bands AT&T will sometimes use the 1900 MHz spectrum exclusively
for 3G UMTS and will provide GSM service only at 850 MHz. A tri-band
GSM phone won't get service in places where AT&T does that.

Apparently, however, where you were did indeed have 1900 MHz
GSM service or your phone wouldn't have been able to register
for service in the first place. I also don't think it works
like you are suggesting with respect to cross-band control. If
your phone managed to find a 1900 MHz control channel to register
on then you should have been able to receive calls as well as
make them.

That leaves two possibilities that I can think of. When AT&T
deploys a 1900 MHz network by simply adding 1900 MHz antennas
to their existing 850 MHz towers they often end up with 1900 MHz
coverage which is full of holes since the towers are too far apart
and/or not tall enough (it was like this where I lived in
California). It is hence possible that while your service may
have shown many-bar signal strength in some places, you may
have been in locations with no service when your incoming calls
arrived and ended up in voicemail.

If you think that's unlikely, however, then I'd suggest the
the problem might have been that AT&T's 1900 MHz service was
simply broken, but AT&T didn't know that since all their local
customers end up on 850 MHz instead and hence never complain
about 1900 MHz problems.

In any case, it is risky to use AT&T service with a 1900-MHz-only
phone. T-Mobile is a better bet at 1900 MHz, but only if you
stick around cities.

Dennis Ferguson

It is a well known fact (at least here in the US), do NOT use a phone
without the 850 band with AT&T. Tmobile is primarily 1900 so folks with
the eurasian triband (900/1800/1900) should go with tmobile. I have
family in the UK, and they all have tmobile US sim they use when they
visit here with their triband phones, and they do not have any problems
at all.

Had you been roaming with that phone, it would have latched on to
tmobile. Yes, AT&T is the bigger carrier with more extensive coverage
of the 2 GSM carriers here, but you definitely need a phone with 850
band in most areas. In some big cities and definitely in remote areas
AT&T uses the 850 band ONLY.




--
mrcamp

On Sat, 28 Jun 2008 22:59:12 GMT, Dennis Ferguson
<[email protected]> wrote:


>If you think that's unlikely, however, then I'd suggest the
>the problem might have been that AT&T's 1900 MHz service was
>simply broken, but AT&T didn't know that since all their local
>customers end up on 850 MHz instead and hence never complain
>about 1900 MHz problems.

The Cingular service wasn't broken - full signal on my tri-band phone
but incoming calls not possible - outgoing calls fine. Took me a
couple of days to realise this as on holiday I don't expect many
calls. In this case I had a real Cingular sim in the 6230i phone.

I wonder if I had had a UK sim in it whether or not the phone could
have sensed there was a problem with the Cingular roaming and switched
to T-mobile. Uk sim roaming not feasible at over £1 per min though.

Incoming with Cingular sim worked fine in my friend's quad band phone
though, so definitely a frequency-related (tri-band v quad-band)
problem.

Can someone from the Vodafone C/s who I know read this group tell us
if their website is indeed wrong and you do need a quad band phone for
Cingular in Florida - not a tri-band as the Voda website says?

Jules.

On Tue, 01 Jul 2008 20:07:19 +0100, Mark <[email protected]>
wrote:

>Just to widen the scope a bit, is this issue also applicable to Rogers
>Wireless in Canada, where it has both 850 and 1900 networks?

I haven't tried that one.

Jules