How IMEI number is generated?

A SIMPLE WAY To check IMEI (International Mobile Equipment Identity) of any mobile,
On the main screen of your mobile type *#06#
your imei number will be displayed
Information you get from the IMEI
XXXXXX XX XXXXXX X
TAC FAC SNR SP
TAC = Type approval code of your Nokia Mobile
FAC = Final assembly code of your cellphone
SNR = Serial number of your Nokia Phone
SP = Spare