Section: 10.4.2 Composition of the IFPEI
Content: 6 digits 2d 6 digits 2d <-----------><---><-----------><---> +-----------++---++-----------++---+ | || || || | +------++--++------++--+ TAC FAC SNR SVN IFPEI 16 digits <> Figure 17: Structure of IFPEI The IFPEI is composed of the following elements (each element shall consist of decimal digits only): - Type Approval Code (TAC). Its length is 6 decimal digits; - Final Assembly Code (FAC). Its length is 2 decimal digits; - Serial NumbeR (SNR). Its length is 6 decimal digits; - Software Version Number (SVN) identifies the software version number of the fixed part equipment. Its length is 2 digits. Regarding updates of the IFPEI: the TAC, FAC and SNR shall be physically protected against unauthorised change (see 3GPP TS 42.009[ Security aspects ]  [36]); i.e. only the SVN part of the IFPEI can be modified.