The DS1205S MultiKey Chip is an enhanced version of the DS1204U Electronic Key which has both a standard 3-wire interface (data, clock, and reset) and a 1-Wire® interface. The DS1205S MultiKey has three secure read/write subkeys which are each 384 bits in length. In addition, there is a 512-bit read/write scratchpad which can be used as a non-secure data area or as a holding register for data transfer to one of the three subkeys. Each subkey within the part is uniquely addressable on byte boundaries. Applications * Financial Transactions * Proprietary Data * Secure Personnel Areas * Systems Access Control * Three secure read/write data partitions of 384 bits each * One non-secure read/write data partition of 512 bits * Secure data cannot be deciphered by reverse engineering * Guaranteed unique, 48-bit, laser etched serial number * 64-bit password and I.D. fields provide positive identification and security for each secure data partition * Maximum data transfer rate of 2 million bits/second * Low-power CMOS circuitry * Access via 3-wire or 1-Wire interface