The IMEI (International Mobile Equipment Identity) is a unique 15 or 17 digit code used to identify an individual mobile station to a GSM or UMTS network. The IMEI number facilitates an important function; it easily identifies a mobile phone being used on a GSM (Global System for Mobile Communications) network. The IMEI is a useful tool to stop a phone that is stolen from accessing a network and being used. Mobile phone owners that have their phones stolen can contact their mobile network provider and ask them to ban or shut off a phone using its IMEI number. With an IMEI number, the phone can be banned from the network quickly and easily. It is important to note that swapping a SIM card will not stop a phone from being banned. An IMEI device is only used to identify the device and does not usually relate to a specific individual or organization. Other numbers such as ESN (Electronic Serial Numbers) and MEID (Mobile Equipment Identifiers) can link an individual to a phone. Usually, an IMSI number stored on a SIM card can identify the subscriber on a network.
There are a few ways in which you can locate your mobile phone's IMEI number, it can usually be found on the handset, beneath the battery, sometimes printed on a small white label. Another way to easily locate your IMEI phone is to dial the following sequence of numbers into the handset: *#06#. If you have a Sony Ericsson mobile phone, you can retrieve the IMEI by pressing the following key sequence: right,*, left, left,*, left, *, left.
The Structure of an IMEI Number

IMEI numbers either come in a 15 digit or 17 digit sequences of numbers. These numbers can identify a handset. Currently the format of the IMEI is AA-BBBBBB-CCCCCC-D.
  • These two digits are for the Reporting Body Identifier, indicating the GSMA approved group that allocated the TAC (Type Allocation Code).
  • BBBBBB- The Remainder of the TAC
  • CCCCCC- Serial Sequence of the Model
  • D- Luhn Check Digit of the entire model or 0 (This is an algorithm that validates the ID number)