A product information display system has electronic display tags (20) for displaying pricing and product information for products in stores and warehouses. The electronic display tags (20) are electromagnetically coupled to a conductor (C1-Cn). A control circuit (31) is used to generate an information signal which contains a tag address and related data. A modulator circuit modulates an a-c power signal with the information signal and applies it to the conductor for transmission to the display tags (20). An electrical power system (28) supplies a-c power to the display tags (20). A main power distribution loop is connected to the power supply (28) and is magnetically coupled to multiple branch power distribution loops which extend along selected groups of display tags (20) for supplying power to those display tags (20).