Wireless transmitter-receiver information device

摘要

The disclosure is of an indoor transceiver system in which first electromagnetic waves at 20 KHz are transmitted from a single loop primary coil in or adjacent a room to a plurality of data storage devices in the same room and having respective multi-turn secondary coils coupled by an induction coupling to such primary coil to receive such waves which provide both operating power and signals for such devices. Each device is responsive to a signal transmitted thereto by such first waves to transmit information from such device via second electromagnetic waves at 900 MHz. Each device has a panel providing a non-volatile display of information which represents the price of goods proximate the device, and which price is updated from time to time by signals transmitted to the device by such first waves.