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International Mobile Equipment Identifier or IMEI PDF Print E-mail

A 15-digit number (composed of four parts) that uniquely identifies an individual wireless device (associated with every mobile phone). The IMEI is automatically transmitted by the phone when the network asks for it. A network operator might request the IMEI to determine if a device is in disrepair, stolen or to gather statistics on fraud or faults.

It is usually found behind the battery and can also be found by dialling *#06# into the phone.

However in Singapore, all the telcos do not implement the blacklisting or baring of IMEI numbers, as it will compromise the performance of mobile networks. However if your phone is stolen, notify your telcos so that your SIM card will be deactivated. This means that your SIM cannot be used to make existing calls, however anyone who uses their own SIM will be able to use the phone as the telcos will not blacklist the phone's IMEI.

Also note that certain mobile applications uses IMEI number to "unlock" the application. Thereafter this application is tied directly to the phone's IMEI number, and if you were to upgrade to a new phone and transfer the application to the new phone. It will no longer work.

To check your IMEI number try the IMEI Number Analysis @ http://www.numberingplans.com/index.php?goto=imei

 

Technical

When a phone is switched on, the IMEI number is transmitted and checked against a database in the network's EIR (Equipment Identity Register). 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 A serial number is a unique number applied to a product example, as opposed to a model number or type number. Each of a series of identical products has a different serial number. The term strictly applies only to numbers that increase by one for each unit (for example, 060001, 060002, 060003), but usage has expanded the term to refer to any unique alphanumeric identifier for one of a large set of objects. 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

ITEM Name Phase 1 Phase 2 Phase 2+
TAC Type
(Approval)/ Allocation Code 		6 Digits (NNXXXX)
NN identifies the Reporting Body and XXXX is the Type Identifier defined by the reporting body. 		8 Digits (NNXXXXXX)
(same as Phase 1 & 2)
FAC Final Assembly Code 2 Digits
Identifies the facility where the phone was manufactured. 		Always set to "00" to allow the industry to move to an 8-digit TAC (limit of 1 million units per TAC). Obsolete from 31/12/2002.
SNR Serial Number Unique 6-digit serial number allocated to a particular unit.
SP Spare Single (not-used) digit, always allocated a value of "0". Obsolete from 31/12/2002.
CD Check Digit Not used. Single-digit whose value depends on the previous 14 digits.

Check Digit
Defined according to the Luhn formula and excludes the SVN digits. The check-digit is not transmitted during IMEI information requests.

SVN
The Software Version Number is a 2-digit field, separate from the IMEI but appended to and associated with it. When the network requests the IMEI to be sent, the SVN (if present) is also sent.

IMEISV
The International Mobile station Equipment Identity and Software Version Number as defined in TS GSM 03.03 is a 16-digit decimal number comprised of 4 elements:

a 6-digit TAC
a 2-digit FAC
a 6-digit SNR
a 2-digit SVN

EIR
The Equipment Identity Register allows a network operator can make administrative use of the IMEI in the following manner:
Three registers are defined, known as "white lists", "grey lists" and "black lists". The use of these lists is at the operators' discretion. The white list is composed of all equipment identities that are permitted to use the network. The black list contains all equipment identities that belong to equipment that is barred from using the network. Network administrations also have the possibility to use a grey list . Equipment on the grey list are not barred (unless on the black list or not on the white list), but are tracked by the network (for evaluation or other purposes.) The white list shall use the IMEI, The Black and Grey Lists may also use the SVN.