The full-page article gives a historical background and explains the main characteristics when using infrared signals for identification, such as safe reading, low cost, easy installation, compactness, insensitivity to radio signals, harmlessness to other systems, tolerance to metal surroundings, rain and moisture, and other inherent properties of light as a transmission medium. The article includes a factbox with detailed information about traditional RFID systems in the LF-, HF-, UHF- and 2.45 GHz/5.8 GHz microwave bands.