On Tue, 19 Jun 2007 17:10:31 -0700, [email protected] wrote in
<[email protected]>:

>I live in Southern California. When I turned my phone on it always said
>Cingular. Today, however, it said AT&T. I am not talking about the splash
>screen when the phone boots up. That still says Cingular. I'm talking
>about the text on top of the wallpaper on the phone.
>
>Anybody know how they did this?
>
>I have a Moto V557 & my phone has a 32K SIM chip.

A. Startup and shutdown screens are typically graphics stored in phone
memory (firmware), thus are not affected by the network or the SIM, and
are typically changed only by updating the firmware, usually only by
cable, although some newer phones can be updated OTA (over the air).

B. Text on menus is also stored in phone memory (firmware), and thus
isn't directly affected by the network, although it can be overridden by
the SIM, which can be re-programmed OTA.

C. GSM/UMTS rules for network display, sometimes referred to as
"operator text" or "alpha tag", but more accurately:
* Public Land Mobile Network (PLMN) name, or
* Mobile Network name (shortened form of the above), or
* Service provider name (SPN) (as stored on the SIM),

1. If Mobile Country Code (MCC) and Mobile Network Code (MNC)
broadcast on the network match the MCC and MNC on the SIM, the
Service Provider Name (SPN) on the SIM is displayed.

2. If the MCC-MNC combination does not match, the phone checks a table
in its firmware for an entry corresponding to the MCC and MNC
received. If found, that entry is displayed.

3. If no table entry is found, the country abbreviation (or the MCC if
no country name entry is found in firmware) and the MNC are
displayed.

SIM programming can be updated OTA, so the Service Provider Name can be
changed. Since that is done on a per SIM basis, different phones may
change at different times.

What AT&T/Cingular is apparently doing is reprogramming SIMs over time
OTA with a new Service Provider Name, but not (yet at least) overriding
menus and/or updating phone firmware.

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


› See More: My screen changed this morning from Cingular ==> AT&T