Mode: IMEI When you enter this number (no need to touch dial afterwards), you should be presented with your 15 digit IMEI number.
mailto://EMAIL_ADDRESS will launch the mail program to compose a message to EMAIL_ADDRESS.
On the i Phone you can enter special phone numbers to access special features or information.
Changing SIM card, you can be tracked by cellphone used.
Location can be narrowed down using IMEI triangulation of cell towers the cellphone is closest to.
It is a unique identification number for every cellphone (including the i Phone).
Many cell networks can ban stolen cellphones using this IMEI number (changing SIM cards have no effect on ban) by checking the EIR (Equipment Identity Register) database downloaded from a central server.
Mode: Connected Line Presentation You will be shown whether Connected Line Presentation is enabled.
If a number you called is actually forwarded to another number, this feature allows you to see the actual number you got forwarded to.
Also be aware that shutting down with the USB device connected implies that you would boot up with it connected. There have been many complaints about handset problems apparently associated with insufficient power. (Prior to this generation, users commonly used the Tiger Jet echo cancellation utility.
It has been reported that this is unnecessary with this new generation.).
As for the frequency you are using, use the following guide to match your ARFCN (Absolute Radio Frequency Channel Number): "Network Operating Mode", if it is NOM 001 then Voice has higher priority (Class A), while NOM 002 indicates Data has a higher priority than Voice (Class B). Note that this Field Test Mode was disabled in i OS 4.0, and re-enabled in i OS 4.2.1.