Abstract: The invention is an apparatus and method for using electromagnetic energy as the means of automatic data collection (ADC). The communication system that comprises the invention utilizes frequency modulated (“FM”) sideband electromagnetic energy to enable full duplex communication with another communication device. In one embodiment one of the communication devices is passive and the carrier is used to power the passive device. In another embodiment the communication devices are active and the carrier is suppressed to increase range or decrease power constraints, as the application requires.

Abstract: A data acquisition system is disclosed where a first communication device transmits a transmitted signal to a second communication device. The second communication device encodes the transmitted signal with a code generating a retransmitted signal. The retransmitted signal is then transmitted back to the first communication device. The code can be indicative of an environmental element, such as a traffic sign. The first communication device can determine a distance to the environmental element by monitoring a time for the retransmitted signal to arrive. The first communication device can also encode the transmitted signal with information, such as voice for example.