The International Mobile Equipment
Identity number uniquely identifies an
individual mobile station. The IMEI is
unique to every ME (Mobile Equipment)
and thereby provides a means for
controlling access to GSM networks based
on ME types or individual units.
The IMEI format is
being originated by the Mobile Telecommunication
Standardisation
Authorities. Nokia cannot bear a responsibility for eventual additional
cost arising from e.g. updating the company
housekeeping system
etc.
The “IMEI” consists of a number of
fields totalling 15 digits. All digits have the
range of 0 to 9 coded as binary coded
decimal. Values outside this range are
not permitted.
The IMEI structure valid
since 01.04.2004 is as follows
NNXXXXXX ZZZZZZ
A
TAC: Type Allocation Code SNR: Serial Number CD: Check Digit
TAC Type
Allocation Code, formerly known as Type Approval Code
NN Reporting Body Identifier, e.g. BABT
XXXXXX Type Identifier defined by Reporting
Body
ZZZZZZ Allocated by Reporting Body but
assigned to individual mobile
Stations by the manufacturer
A Phase 1 = 0
Phase 2 & 2+ = Check digit,
defined as a function of all other
IMEI digits.
IMEI
structure until 31.12.2002
The IMEI structure valid
until 31.12.2002 is as follows
NNXXXX YY XXXXXX A
TAC FAC SNR CD
TAC: Type Approval Code
FAC: Final Assembly Code
SNR: Serial Number SNR: Serial Number
CD: Check Digit
The meaning of the acronyms
for the IMEI format valid until 31.12.2002 is:
TAC Type
Allocation Code, formerly known as Type Approval Code
NN Reporting Body
Identifier
XXXX ME Type Identifier
defined by Reporting Body
FAC Final
Assembly Code
YY Under control of the
Reporting Body. May be used to indicate
the manufacturing site.
More than one FAC per site should be
used to permit production
of greater than 1000000 ME.
A Phase 1 = 0
Phase 2 (0r later) = Check
digit, defined as a function of all other IMEI digits.
IMEI
structure 01.01.2003 to 01.04.2004
Structure has changed to
combine the TAC and FAC into a single eight-digit
TAC code.
To allow e.g. the operators
to modify theirs systems to use the eight digit
TAC rather than a six digit
one and the manufacturers to make any
necessary changes to their
production processes, a transition period has
been determined to be from
31.12.2002 to 01.04.2004.
To achieve this transition,
all eight-digit TAC codes allocated between
31.12.2002 and 31.03.2004
will have unique combinations of the first six
digits (NNXXXX) with the
seventh and eight digits (YY) being fixed to 00.
The IMEI structure valid
from until 01.01.2003 to 01.04.2004
NNXXXX 00 ZZZZZZ A
TAC FAC SNR CD
TAC: Type Approval Code
FAC: Final Assembly Code
SNR: Serial Number
CD: Check Digit
