Abstract: A dual frequency radio tag for a radio frequency identification system is provided that includes an antenna system and a first receiver coupled to the antenna system. The first receiver receives and processes request signals from a first unit type at a first frequency. A second receiver is coupled to the antenna system and receives and processes request signals from a second unit type at a disparate second frequency. A transmitter is coupled to the antenna system and transmits response signals from the radio tag at the second frequency.

Abstract: A radio frequency tag for a radio frequency identification system is provided that includes an antenna and a receiver coupled to the antenna. The receiver receives and demodulates a message received on at least one frequency. A retransmit controller receives the message, determines a retransmit status for the message, and if the retransmit status is positive, initiates retransmission of the message for reception by another radio tag.