WARNING: Using secret codes may be harmful to your phone and result in disabling or worse. Use these codes at your own discretion, we accept no responsiblility for blocked pones while using these codes!!! 
IMEI Number
*#06# Cells Identity Code (IMEI = International Mobile Equipment Identity)
XXXXXX XX XXXXXX X
TAC FAC SNR SP 
TAC = Type Approval Code (first 2 digits = country code of the approval-country )
FAC = Final Assembly Code: (01,02 = AEG)
(10,20 Nokia)
(40,41,44 Siemens)
(30 Ericsson)
(50 Bosch)
(51 Sony,Siemens,Ericsson)
(60 Alcatel)
(65 AEG)
(70 Sagem)
(75 Dancall)
(80 Philips)
(85 Panasonic) 
SNR = Serial Nr. 
SP = Spare (always "0")