Updating cell phone towers
On the i Phone you can enter special phone numbers to access special features or information.
These numbers (or codes) work on most GSM capable phones, and the i Phone is no exception.
Normally if you were using a computer to access something like Gmail, your browser would automatically do the lookups for you and figure out the latest address that the site is on, and connect to the appropriate place.
In the case of a phone, it’s not quite that simple as there are a lot of pieces to the puzzle.
facetime://CONTACT will pop up a dialog asking if you wish to make a video call to CONTACT using Apple's Facetime over Wi-Fi.
mailto://EMAIL_ADDRESS will launch the mail program to compose a message to EMAIL_ADDRESS.
However, many of field test features listed are no longer available unless you use an earlier version of the firmware, or re-enable via homebrew.
Mode: IMEI When you enter this number (no need to touch dial afterwards), you should be presented with your 15 digit IMEI number.
For instance, if Verizon decides to make some changes to their network to adjust the frequency of their signal, or is migrating to a new system, they need a way to tell your i Phone about this, so they push out an update to everybody as a small settings file as opposed to a full i OS update.IMEI stands for International Mobile Equipment Identity.It is a unique identification number for every cellphone (including the i Phone).Changing cellphone, you can be tracked by SIM card used.Changing SIM card, you can be tracked by cellphone used.