Infrared signals used for short range communication. It has the frequency range from 300 GHz to 400 THz. It has wavelength from 1 mm to 770 mm. Infrared communications is achieved by using the transmitters/ receivers that modulate infrared light. Transceivers must be within the line of sight of each other directly or via reflection. One disadvantage of infrared is that is dose not penetrate walls. We can not use infrared outside a building because…"Wireless Transmission and Infrared Waves."