The International Mobile Equipment Identity (or IMEI) is a unique number associated with every GSM and UMTS 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 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 Phase 1 phones this is a zero.

For example the code 352099-00-176148-1 tells use the following:
TAC: 352099 so it was approved in Finland (35) and has the approval number 2099
FAC: 00 so it was number during the transition phase from the old format to the new format (described below)
SNR: 176148
CD: 1 so it a GSM Phase 2 or higher

The format changed from the 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 increased 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 possessing equipment that can change it, is considered an offence under some circumstances.

External link

• IMEI Number Analysis: By entering a valid IMEI it will tell you all known information on that phone.

• IMEI Tracking Software: A Point of Sales Software Solution for Mobile Retail Store to track the IMEI of handset being Purchased, Sold, Consigned, Returned, Stock Transferred to Branch, Serviced, Replaced, etc., and maintaining the History of IMEI Handset across the branches.