Infrared requires line of sight in order to transmit information. Think about the functionality of a TV remote, it will not work with any obstacles in the way, and you must be at a reasonably close distance, with a direct line of sight. Radio frequency (RF) has much longer wavelengths, meaning that it does not require line of sight to transmit successfully; it transmits around obstacles and to a greater distance. This means the infrastructure for RF technology is minimal, with small stores only requiring a single box to be installed in the ceiling, compared to the network of wiring required for IR.