IMEI

The International Mobile Equipment Identity (or IMEI) is a unique number associated with every mobile phone. It is usually found printed on or underneath the phone's battery and can also be found by dialling the sequence *#06# into the phone.

The IMEI number is used by the GSM network to identify valid devices and therefore can be used to stop a stolen phone from accessing the network. For example, if a mobile phone is stolen, the owner can call his or her network provider and instruct them to "bar" the phone using its IMEI number. This renders the phone useless, regardless of whether the phone's SIM card is changed.

Structure of the IMEI

It is 15 digits long and broken up like nnnnnn-nn-nnnnnn-n. The first six digits are the Type Approval Code that identifies where permission for that phone was first sought. The next two digits are the Final Assembly Code, which identify the company that manufactured the phone. The next six digits are the Serial number and is unique to that phone. The last digit is a check digit. For April 1, 2004 when the Final Assembly Code will no longer exist and the Type Approval Code will become eight digits in length and be known as the Type Allocation Code. From January 1, 2003 until this time the FAC for all phones will be 00.

IMEI and law

Many countries have acknowledged the use of the IMEI in reducing the effect of mobile phone theft, which has increase exponentially over the last few years. For example, in the United Kingdom, under the Mobile Telephones (Re-programming) Act, changing the IMEI of a phone or posessing equipment that can is considered an offence under some circumstances.