US Patent 7479873 Vehicle tag reader

A tire sensor that communicates to a remote interrogator in one of two modes depending on the nature of the interrogation. The interrogator may be distributed throughout a vehicle if needed for design options. Further, the interrogator only interrogates the transponder when the interrogator has reason to believe that the transponder is in range of the interrogator. The interrogator and transponder may be configured to operate in different modes for communication during operation of the tire on a vehicle and during non-operation. The transponder may communicate tire condition information to the interrogator concerning environmental or other information sensed about the tire.