Method of enabling two-state operation of electronic toll collection system

摘要: A method and system for communicating state information from a transponder to reader. The outputs linearly polarized RF signals having either first polarization, such as horizontal, or second vertical. polarization is selected so indicate state. reader detects whether received have the thereby determines of transponder. In some embodiments, may include two antennas, one with receiving determining signals. be implemented within an electronic toll collection system, wherein transponders are affixed interior vehicle windshields using rotatable mounting mechanism selectable positions.