Definition: IMEI

(International Mobile Equipment Identity) A unique number assigned to a GSM, UMTS or IDEN cellphone. The IMEI identifies the phone model and serial number, whereas the IMSI (international mobile subscriber identity) number identifies the user. The equivalent of IMEI in a CDMA cellphone is the electronic serial number (see ESN) or mobile equipment ID (see MEID). See IMSI.

The first eight digits of the IMEI are the type allocation code (TAC) as follows:

  IMEI CODE FORMAT

  Digits  Contain
  1-2    Reporting body (CTIA, TUV, etc.)
  3-8    Brand and model
  9-14   Serial number
  15     Check digit