The memory is organized in a Main Memory of· 64 byte for SLE 4440· 128 byte for SLE 4441· 256 byte for SLE 4432 and SLE 4442Each of the first 32 bytes of the Main Memory can be irreversibly protected against data changeby writing the corresponding bit in the Protection Memory (32 bit). Dependent on the state of theprotection bit the memory is read only (ROM) or may be erased and written again (EEPROM).Change of the manufacturer code is only possible by the chip manufacturer.Change of data of the Main Memory and write a bit of the Protection Memory is only possibleafter a correct verification of the Programmable Security Code (PSC) for SLE 4440, SLE 4441and SLE 4442.