Patent attributes
A RF data communication device operates in at least two states. In a first state, the device transmits a response to an RF transmission if specific data therein represents an inquiry as to the presence of one or more RF data communication devices and if specific data therein corresponds to a class maintained by the device. The device does not transmit a response if specific data in the RF transmission is not representative of an inquiry as to the presence of one or more RF data communication devices, or if specific data therein does not correspond to at least one maintained class. In a second state, the device does not transmit a response when specific data is included therein that is representative of an inquiry as to the presence of one or more RF data communication devices and specific data therein corresponds to at least one maintained class.