How to generate a valid IMEI number

Discussion in 'Wireless Internet' started by Elmo, Jan 27, 2010.

  1. Elmo

    Elmo Guest

    What is the algorithm for the checksum for an IMEI number?

    Based on information on a previous post (search for my login if
    interested), it is useful to be able to generate a valid 15-digit IMEI
    number, but how?

    As we all know, it's useful to have in your mental toolbox the ability to
    generate valid PC:MAC addresses, valid address:phone numbers, valid
    street:zip codes, valid vehicls:VINs, valid appliance:serials, etc. ... but
    how does one generate a valid IMEI number?

    Do you know what the IMEI number-generation algorithm is?
     
    Elmo, Jan 27, 2010
    #1
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  2. Elmo

    alexd Guest

    alexd, Jan 27, 2010
    #2
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  3. Elmo

    Elmo Guest

    Yup. What happened was I've been paying about $145/month for the Blackberry
    with world access and full data and blackberry enterprise and whatever.

    Then my needs changed, about a year and a half into the plan. I called 611
    from my Blackberry to remove all the stuff I no longer needed but the
    customer support gal wouldn't get rid of the data plan solely because it
    was a blackberry (not, I remind you, not because they subsidized it as they
    subsidize all phones initially).

    I argued that I could easily move the SIM card to an unlocked Motorola RAZR
    and she said if I did that, then I could remove the data plan. I told her
    then remove it, and she said no, because I was using the blackberry.

    So I asked for her supervisor. When the supervisor came on line, she
    already knew what I wanted. She told me I could only remove the data plan
    if I changed the phone so I told her I changed the phone right then and
    there. I was with a friend so we took out his Motorola RAZR and changed the
    last digit. She didn't seem to care. She dropped the data plan.

    The only drawback I can see is she also dropped the warranty but that's a
    small price to pay to save about 50 bucks a month (taxes and stuff
    included).
     
    Elmo, Jan 28, 2010
    #3
  4. Elmo

    Elmo Guest

    This forum only discusses how to calculate the checksum; I was looking for
    the whole IMEI number generation.

    For example, to generate a valid MAC address is easy, if you have a table
    of manufacturers' assigned OIDs.
    Ah, this is more to the task.

    The most interesting fact I learned from that article is that 10% of all
    the IMEI numbers out there are not unique!

    I also learned from that article that, like the MAC address on a PC, one
    can change the IMEI number on a particular telephone (if they know how).

    Again, similar to MAC addresses, it looks like IMEI numbers are allocated
    to the manufacturer by a standards body.

    So, the good news is that I can probably find software to generate a valid
    IMEI number given some input parameters (sort of like what MacMakeUp or
    SimpleMac or MadMacs does for the PC).

    I'll summarize the algorithm separately as this post is getting long.
     
    Elmo, Jan 28, 2010
    #4
  5. Elmo

    Elmo Guest

    Based on that article, IMEI numbers are not necessarily unique and the IMEI
    number of a cellphone can be changed (similar to MAC addresses in a PC).

    Also very interesting is that the checksum (last digit) is "never
    transmitted". Hmmmmmm.... it's interesting that the last digit is not
    "seen" by AT&T's hardware ...

    I'll try to summarize the IMEI generation steps in a later post because the
    first step in generating a valid 15-digit IMEI number for any cellphone is
    understanding what the number means.
     
    Elmo, Jan 28, 2010
    #5
  6. Elmo

    Elmo Guest

    The Wikipedia article says the last digit (checksum) isn't transmitted to
    AT&T, so, maybe that's why it didn't matter. Dunno.

    Since IMEI numbers are not unique and since any cellphone can have it's
    IMEI number changed, here's the algorithm for a typical year 2004 15-digit
    IMEI number "AA-BBBBBB-CCCCCC-D", where ...

    AA-The first two digits apparently indicate the issuing agency.

    BBBB-The next four digits seem to indicate the "allocation number" by that
    issuing agency.

    BB-The next two digits indicate the Final Assembly Code (i.e., the location
    of the manufacturers' manufacturing facility).

    CCCCCC-The next six digits are the serial number of the telephone.

    D-the last digit is the checksum digit, which is ALWAYS transmitted to the
    network as a 0.

    Apparently that non-transmitted checksum is calculated by adding the 1st +
    2(2nd) + 3rd + 2(4th) + 5th + 2(6th) + 7th + 2(8th) + 9th + 2(10th) + 11th
    + 2(12th) + 13th + 2(14th) digits and then adding a 15th digits such that
    the resulting addition ends up with a zero on the end.

    One way to generate a valid IMEI number is to enter numbers into this
    website until they generate the type of cellphone you want to emulate:
    http://www.numberingplans.com/?page=analysis&sub=imeinr
     
    Elmo, Jan 28, 2010
    #6
  7. Elmo

    argue not Guest

    Here's a list of valid Final Assembly Codes to help in the generation of a
    valid IMEI number. I don't see RIM here so this list must not be all
    inclusive.

    FAC Code
    01 AEG
    02 AEG
    07 Motorola
    40 Motorola
    10 Nokia
    20 Nokia
    30 Ericsson
    40 Siemens
    41 Siemens
    44 Siemens
    50 Bosch
    51 Sony, Siemens, Ericsson
    60 Alcatel
    61 Ericsson
    65 AEG
    70 Sagem
    75 Dancall
    80 Philips
    85 Panasonic
     
    argue not, Jan 28, 2010
    #7
  8. Elmo

    Mike S. Guest

    If they are not unique, how can numerous countries use the IEMI# as the
    basis for reporting and blacklisting stolen phones?
     
    Mike S., Jan 28, 2010
    #8
  9. Elmo

    Elmo Guest

    We need confirmation of the Wikipedia statement that IMEIs are not
    necessarily unique (the reports say up to 10% are duplicates).

    Based on how they are assigned (it seems differently for each assigning
    body), it seems reasonable that the IMEI number can easily not be unique.

    You can still blacklist the number. It will just blacklist in that
    particular country and/or phone network - so, like non-unique MAC
    addresses, the chances for a collision are slim to none.

    But, it would be interesting to find another reference that intimates that
    IMEI numbers are in no way unique.
     
    Elmo, Jan 29, 2010
    #9
  10. Elmo

    Elmo Guest

    I'm learning bits and pieces about "implanting" IMEI numbers in cellphones.

    Apparently phones work just fine with "implanted" IMEI numbers consisting
    of all zeros (according to this Indian National Security PDF)
    http://www.dot.gov.in/as/2008/Requirements for Natilonal Security_10.10.08.pdf

    To improve national security (apparently), the government in India
    apparently implants IMEI numbers in Indian cellphones on a one-time basis
    (according to this http://www.msai.in/gii.html).

    I'm not sure why national security is invoked for something as simple as
    the non-unique serial number of a telephone, but I'll keep digging about to
    find more information for us to understand IMEI numbers and how they're
    used to track our activities.
     
    Elmo, Feb 1, 2010
    #10
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