Patent ID: 7054657

Claim:
A method for use with a mobile station of a type that stores a 14 digit International Mobile Equipment Identity (IMEI) code for generating a Check Digit (CD), comprising steps of: executing a preliminary step of encoding the 14 digit (D 1 , D 2 , D 3 , . . . , D 14 ) IMEI in a hexadecimal representation; then computing the CD by, (A) doubling the values of the odd digits (D 1 , D 3 , D 5 , . . . , D 13 ) of the IMEI using the hexadecimal number base; (B) adding together the individual digits of the seven numbers obtained in Step A, and adding this sum to the sum of all of the even labeled digits (D 2 , D 4 , D 6 , . . . D 14 ) of the IMEI using the hexadecimal number base; and (C) if the number obtained at the end of Step B ends in zero (0), setting the CD to zero (0), else if the number obtained at the end of Step B does not end in zero (0), setting the CD to be the difference between that number subtracted from the next highest hexadecimal number which does end in zero (0).