no roaming signal

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tmoran@acm.org - 26 Feb 2006 17:09 GMT

In the last month I've gotten zero bars in Dulles airport on my Motorola
T720 with new SIM card, and zero bars on my son's several year old Nokia
in downtown Chicago with old SIM card. Cingular says everything is set up
right and should work, and therefore it must be a problem in the phone.
There are no other symptoms of problems, and both phones worked in Chicago
last June. I did change (Family Talk) plans in mid-November and they
still haven't gotten the billing right - could there be something wrong with
their system that would show up as zero bars? Or are both phones dying?

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John Navas - 27 Feb 2006 16:09 GMT

>In the last month I've gotten zero bars in Dulles airport on my Motorola
>T720 with new SIM card, and zero bars on my son's several year old Nokia
[quoted text clipped - 4 lines]
>still haven't gotten the billing right - could there be something wrong with
>their system that would show up as zero bars? Or are both phones dying?

You might want to try a more modern phone with support for ENS. See the FAQ
below for details.

Signature

Best regards, SEE THE FAQ FOR CINGULAR WIRELESS AT
John Navas <http://en.wikibooks.org/wiki/Cingular_Wireless_FAQ>

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tmoran@acm.org - 28 Feb 2006 18:30 GMT

> >In the last month I've gotten zero bars in Dulles airport on my Motorola
> >T720 with new SIM card, and zero bars on my son's several year old Nokia
[quoted text clipped - 4 lines]
> ...
> John Navas <http://en.wikibooks.org/wiki/Cingular_Wireless_FAQ>

So as I understand it:
1) The T720 is not ENS and thus its new SIM card makes no difference.

2) Even with an ENS phone with new SIM, if I want the best signal, I'd
have to call up Cingular whenever I'm about to travel to a new place, and
ask them to set the phone to use the appropriate network at that place.

3) I gather there is no Cingular signal in Dulles airport (it didn't show
few bars - it showed zero bars), and the phone only looked for Cingular
(or whoever Cingular used to roam with at Dulles before the merger) - it
didn't look for ATT. And the Nokia must also be looking for Cingular's
old partner in Chicago, which also apparently no longer exists.

4) So these phones used to roam various places via local Cingular
partners, but those partners have been dropped and replaced by ATT, which
the phones don't talk to. So in essence, the old roaming abilities, that
worked with my phones, have been dropped, and new roaming (via ATT) is
only available with new phones?

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John Navas - 28 Feb 2006 19:54 GMT

>> >In the last month I've gotten zero bars in Dulles airport on my Motorola
>> >T720 with new SIM card, and zero bars on my son's several year old Nokia
[quoted text clipped - 6 lines]
>
> So as I understand it:

>1) The T720 is not ENS and thus its new SIM card makes no difference.

The new 64K ENS SIM only makes a difference with an ENS-capable device. That
difference is home network selection (between "blue" and "orange") OTA (over
the air) by Cingular.

Another possible issue is band coverage and support. The problem with your
son's phone might be that it doesn't have support for the GSM850 band that's
used by Cingular in many areas. If so, the only solution is to upgrade to a
phone that supports both the GSM850 and GSM1900 bands. This can be easily
checked by taking the phone into a local Cingular company store (preferred) or
independent dealer (which is often hard to distinguish from a company store).

>2) Even with an ENS phone with new SIM, if I want the best signal, I'd
>have to call up Cingular whenever I'm about to travel to a new place, and
>ask them to set the phone to use the appropriate network at that place.

Correct -- but you normally wouldn't do that -- you'd select a "home" network
based on signal quality in the locations that are (1) most important to you
and (2) where ENS makes a significant difference. It most cases ENS doesn't
matter very much.

>3) I gather there is no Cingular signal in Dulles airport (it didn't show
>few bars - it showed zero bars), and the phone only looked for Cingular
>(or whoever Cingular used to roam with at Dulles before the merger) - it
>didn't look for ATT. And the Nokia must also be looking for Cingular's
>old partner in Chicago, which also apparently no longer exists.

Until the orange and blue networks are merged (expected to happen sometime
this year), Cingular handsets homed on orange will look for blue, but won't
select it when there is a "usable" orange signal. Likewise any roaming
partner networks that might be available.

>4) So these phones used to roam various places via local Cingular
>partners, but those partners have been dropped and replaced by ATT, which
>the phones don't talk to.

That might or might not be true -- it might simply be that a roaming network
isn't now being selected because there is now a "usable" home network signal.

>So in essence, the old roaming abilities, that
>worked with my phones, have been dropped, and new roaming (via ATT) is
>only available with new phones?

Hard to say.

Roaming is controlled in part by a PLMN* list stored on the SIM, which is
updated OTA by a special kind of SMS messaging. Call Customer Care and ask
that the latest "roaming list" be "pushed" to your phones.

(* PLMN = Public Land Mobile Network, as distinct from PSTN or Public Switched
Telephone Network.)

Signature

Best regards, SEE THE FAQ FOR CINGULAR WIRELESS AT
John Navas <http://en.wikibooks.org/wiki/Cingular_Wireless_FAQ>

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