Patent ID: 7912442

Claim:
A method of tracking inventory, the method comprising: positioning an interrogator unit in a first region, the interrogator unit comprising one or more transceivers communicatively coupled to one or more antennas, the interrogator unit being configured to transmit radio frequency (RF) signals; transmitting by the interrogator unit via at least one of the one or more transceivers a first RF signal; receiving by a first RFID tag the first RF signal; transitioning to a first mode by the first RFID tag when the first RFID tag determines the first RF signal is at a first frequency and a first data rate; and transitioning to a second mode by the first RFID tag when the first RFID tag determines the first RF signal is at a second frequency and a second data rate, the first RFID tag remaining in the first mode until transitioning into the second mode upon receipt of the first RF signal at the second frequency and the second data rate, and the first RFID tag remaining in the second mode until transitioning into the first mode upon receipt of the first RF signal at the first frequency and the first data rate.