The DS1977 is a 32Kbyte EEPROM in a rugged, iButton enclosure. Access to the memory can be password-protected with different passwords for readonly and full access. Data is transferred serially via the 1-Wire protocol, which requires only a single data lead and a ground return. Every DS1977 is factorylasered with a guaranteed unique 64-bit registration number that allows for absolute trace-ability. The durable stainless steel iButton package is highly resistant to environmental hazards such as dirt and shock. Accessories permit the DS1977 iButton to be mounted on almost any object, including containers, pallets and bags.