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 sun’s rays contain infrared waves which can interfare with the communication.
When we infrared remote control, we do not interfare with the use of remote by our neighbours. It can be used for digital data transmission with high data rate.
As no licensing is required, there is no frequency distribution issue in case of infrared. The association that has steup standards for communication is called Infrared Data Association. IrDA port is used to communicate a wireless keyboard to communicate with PC.