SIEMENS® SLE4442 contact chip card. Synchronous communication protocol, ISO 7816 compatible. EEPROM size is 256 bytes (split into the following areas: 26 bytes for card manufacturer data, 2 bytes for card issuer reference, 4 bytes for card identification data, 224 bytes for main user data). Access to the memory is protected by a 3 byte secret code for data write only. Free Read of Data (except PIN). Data retention is up to 10 years. Non reversible byte-wise write protection of lowest 32 addresses.