Abstract: A system includes a transmit unit to transmit a signal including a data key, and a receiving unit to receive the signal. The receiving unit to determine an encryption key based at least in part on the data key and to decrypt encrypted data using the encryption key.

Abstract: A series of radio frequency identification (RFID) systems are delineated. An RFID system comprises an RFID signpost having a transmitter for transmitting signals of a predefined type, and a receiver for receiving signals of the predefined type, wherein the transmitter for transmitting signals of the predefined type cannot transmit until a determination is made that the predefined type of signal is not present at the receiver. Another RFID system comprises an RFID signpost including a transmitter having a continuous power dissipation rating, and a processor for controlling the transmitter such that peak pulse power of a transmission from the transmitter multiplied by its duty cycle does not exceed the continuous power dissipation rating for the transmitter.

Abstract: A series of radio frequency identification (RFID) systems are delineated. An RFID system comprises an RFID signpost having a transmitter for transmitting signals of a predefined type, and a receiver for receiving signals of the predefined type, wherein the transmitter for transmitting signals of the predefined type cannot transmit until a determination is made that the predefined type of signal is not present at the receiver. Another RFID system comprises an RFID signpost including a transmitter having a continuous power dissipation rating, and a processor for controlling the transmitter such that peak pulse power of a transmission from the transmitter multiplied by its duty cycle does not exceed the continuous power dissipation rating for the transmitter.

Abstract: A series of radio frequency identification (RFID) systems are delineated. One such RFID system comprises an RFID signpost, and a plurality of infrared transmitters, wherein each infrared transmitter of the plurality of infrared transmitters is arranged to cover, when transmitting, a distinct sector relative to the RFID signpost. Another RFID system comprises an RFID signpost having a transmitter for transmitting signals of a predefined type, and a receiver for receiving signals of the predefined type, wherein the transmitter for transmitting signals of the predefined type cannot transmit until a determination is made that the predefined type of signal is not present at the receiver.

Abstract: A tamper monitoring system includes at least one active tag and a transmission link. The one active tag includes a transmitter and a receiver. The first end of the transmission link is connected to the transmitter and the second end is connected to the receiver. The transmitter is designed to transmit a non-constant signal to the transmission link to the receiver, and the receiver is designed to receive a signal from the transmission link and to correlate the received signal with the transmitted signal. When the received signal does not correlate with the transmitted signal, the active tag transmits a tamper beacon.

Abstract: A system includes a transmit unit to transmit a signal including a data key, and a receiving unit to receive the signal. The receiving unit to determine an encryption key based at least in part on the data key and to decrypt encrypted data using the encryption key.

Abstract: A series of radio frequency identification (RFID) systems are delineated. One such RFID system comprises an RFID signpost, and a plurality of infrared transmitters, wherein each infrared transmitter of the plurality of infrared transmitters is arranged to cover, when transmitting, a distinct sector relative to the RFID signpost. Another RFID system comprises an RFID signpost having a transmitter for transmitting signals of a predefined type, and a receiver for receiving signals of the predefined type, wherein the transmitter for transmitting signals of the predefined type cannot transmit until a determination is made that the predefined type of signal is not present at the receiver.

Abstract: A tamper monitoring system includes at least one active tag and a transmission link. The one active tag includes a transmitter and a receiver. The first end of the transmission link is connected to the transmitter and the second end is connected to the receiver. The transmitter is designed to transmit a non-constant signal to the transmission link to the receiver, and the receiver is designed to receive a signal from the transmission link and to correlate the received signal with the transmitted signal. When the received signal does not correlate with the transmitted signal, the active tag transmits a tamper beacon.