The DS1972 is a 1024-bit, 1-Wire EEPROM organized as four memory pages of 256 bits each in a rugged iButton package. Data is written to an 8byte scratchpad, verified, and then copied to the EEPROM memory. As a special feature, the four memory pages can individually be write protected or put in EPROM-emulation mode, where bits can only be changed from a 1 to a 0 state. The DS1972 communicates over the single-conductor 1-Wire bus. The communication follows the standard Dallas Semiconductor 1-Wire protocol. Each device has its own unalterable and unique 64-bit ROM registration number that is factory lasered into the device. The registration number is used to address the device in a multidrop 1-Wire net environment.