IMEI Format

IMEI number is structured by the British approvals Board for Telecommunication (BABT). It has 15 decimal digits. Actualy it has 14 digits plus a check digit.

First 8 digits of IMEI number are Type Allocation Code (TAC) which will give you the mobile phone brand and model. Other 7 digits are defined by manufacturer (6 are serial number and 1 is check digit).

From 2004, the format of the IMEI is AA BBBBBB CCCCCC D.

TAC SERIAL CHECK DIGITAA BBBBBB CCCCCC D

In any of the above cases, the first two digits of the TAC are the Reporting Body Identifier (RBI), which identifies the GSMA-approved group that allocated the TAC. The RBI numbers are allocated by the Global Decimal Administrator. The first two digits are always decimal (i.e., less than 0xA0), allowing IMEI numbers to be distinguished from an MEID, which will always have 0xA0 or larger as its first two digits.

The Type Allocation Code (TAC) is the initial eight-digit portion of the 15-digit IMEI code used to uniquely identify wireless devices.

The Type Allocation Code identifies a particular model (and often revision) of wireless telephone for use on a GSM, UMTS or other IMEI-supporting wireless network.

The first two digits of the TAC are the Reporting Body Identifier. This indicates the GSMA-approved group that allocated the TAC.

Prior to April 1, 2004, the global standard for the IMEI started with a six-digit Type Approval Code followed by a two-digit Final Assembly Code (FAC). The Type Approval Code (also known as TAC) indicated that the particular device was approved by a national GSM approval body and the FAC identified the company that had built and assembled the device (which is not always the same as the brand name stamped on the device).

Effective on that date, many GSM member nations and entities (mainly Europe) moved away from requiring that devices be approved by national bodies, and towards a system where device manufacturers self-regulate the device market. As a result, a manufacturer now simply requests an eight-digit Type Allocation Code for a new phone model from the international GSM standards body, instead of submitting a device for approval to a national review body.

Both the old and new TAC uniquely identify a model of phone, although some models may have more than one code, depending on revision, manufacturing location, and other factors.

Example of IMEI number 35 780502 398494 2 structure:

35 is reporting body identifier.780502 manufacturer and brand (phone type)398494 serial number2 check digit

Reporting Body Identifier codes

The Reporting Body Identifier is the first two digits of a GSM Type Allocation Code, and indicates the GSMA-approved organization that registered (or, before 2002, approved) a given mobile device, and allocated the model a unique code.

The numbers are loosely based on the telephone country codes of the organization identified, as most approving nations used a single approval body endorsed by their national GSM Association chapter. However, not all RBIs follow this tendency.

Code Group/indication Origin00 Test IMEI Nations with 2-digit CCs01 PTCRB United States02 - 09 Test IMEI Nations with 3-digit CCs10 DECT devices30 Iridium United States (satellite phones)33 DGPT France35 BABT United Kingdom44 BABT United Kingdom45 NTA Denmark49 BZT / BAPT Germany50 BZT ETS Germany51 Cetecom ICT Germany52 Cetecom Germany53 TUV Germany54 Phoenix Test Lab Germany86 TAF China91 MSAI India98 BABT United Kingdom99 GHA For multi RAT 3GPP2/3GPP