The DS1205V MultiKey has three, 384-bit read/write data partitions, each protected by its own 64-bit I.D. and security match fields. The security match field, programmed by the customer, can never be read from the DS1205V. An additional security feature, the Intelligent Response generator, uses invalid security match codes as the "seed" to trigger seemingly valid, yet false responses to electronic attack. Communication with the DS1205V is via the Dallas 3-Wire Interface (Data, Clock, Reset). These signals are under host software control.