Protected items are stored in the lower addresses of the user EEPROM memory and are numbered starting with zero.
Items’ number names are stored in the Protected Item Root Table (PIRT). Each element of the table occupies 2 bytes. Items’ number names should not match. Number names of 0xFF00 and above are reserved and their use is highly not recommended.
EEPROM memory addresses corresponding to the protected item descriptors are stored in the Protected Item Allocation Table (PIAT). A protected item with respective number corresponds to each 16 bit element of this table.
The memory area used for storing descriptors is usually protected with hardware locks for reading and writing. This prevents from learning, copying and/or modifying the protected items.