I would like to know why each of the mobile phone models understand the network name differently. I would like to illustrate the following situation.
Test Mobile Models: Nokia 3315, Nokia 6030, Nokia 1108, Motorola T 190
Network (GSM): Airtel Chennai, Aircel Tamil Nadu
When we switch on the mobile model, the following are shown as logged on network.
3315: INA Airtel
6030: IND Airtel
T 190: SkyCell (SkyCell has been the old name of Airtel till 1993 and then it was changed by them)
Similarly, for Aircel, a combination of values like Aircel, INA Aircel, RPG, RPG MAA are shown.
I would like to know how these are propagated. I am sure the SIM Card would not have these stored in its network since in Roaming, this might be different. How come the handset is able to get the very old name and/or the most latest name dynamically? Would the GSM networks preserve and send all the info in the signals it propagates.