The imei is a unique serial number assocaited with each phone. Its actual name is International Mobile Equipment Identity, and it is usually found behind the battery on the phone on a white label as in the example below.
The imei number is always 15 digits in length and the imei number is broken down into 4 groups like in the example above
xxxxxx / xx / xxxxxx / x
The first set of numbers are called the TAC (Type approval code) the first two digits of which represent the country code and the other 4 make up the final assembly code.
The second group of numbers identify the manufacturer of the handset like the examples below :
01 and 02 = AEG
07 and 40 = Motorola
10 and 20 = Nokia
41and 44 = Siemens
51= Sony, Siemens, Ericsson
The third set is the serial number of the handset and the last number is just an additional number.
You can also find out your phones imei number by pressing *#06# on the handset whilst it is switched on. This will display the number on your phones screen.
People will often talk about an imei number being barred. This is when a network provider prevents a handset from making / receiving calls on its database usually because the phone has been reported stolen or the user has not paid their bills. Although imei numbers can be changed to fool the network into believing it is not a stolen handset it is illegal to change them and can result in a jail sentence if caught.
