IMEISV (International Mobile Station Equipment Identity Software Version) is the code that identifies the mobile phone and the version of its software.
It consists of the following elements:
- Type Approval Code (TAC) - TAC code 6 digits long
- Final Assembly Code (FAC) - code identifies the place of the final production stage and consist of 2 digits
- Sequence Number (SNR) - individual sequence number uniquely identifying each device among others having the same TAC and FAC, 6 digits long
- Software Version Number (SVN) - identifying the software version number of the mobile device, 2 digits long
Diagram of the construction of the international mobile station identification number, including software version (IMEISV):
6 digits (TAC) + 2 digits (FAC) + 6 digits (SNR) + 2 digits (SVN) = IMEISV (16 digits)
Each IMEISV element can contain only decimal numbers.
By marking the devices, the manufacturer protects TAC, FAC and SNR against unauthorized changes. The TAC type approval code is determined by the GSMA and the final location of the FAC device is coded by the manufacturer.
How to check IMEISV?
IMEISV can be found in the phone menu. Number is usually located on the phone box.
CHECK IMEI 
