Self-Energized Credential System

Sandia Laboratories has developed a system that will automatically detect the passage of personnel or material having a coded electronic credential into or out of controlled areas. The credential is activated by the presence of an alternating magnetic field and responds by transmitting a stored code along with necessary synchronization and parity bits to a receiver where it is detected and decoded. After decoding, the received identification word is available for use by a computer or for visual display to security personnel.