Infrared communication (IR) is an example of wireless communication. However, it is limited to very simple applications & suffers from several disadvantages, mainly very small bandwidth & distances that it can support. Infrared communication works in the micrometer range, which is 1 to 430 THZ. The term infrared comes from the fact that red color has the longest wavelength amongst the colors in visible light. However, the wavelength of infrared is longer than that of red color, and hence the frequency of infrared communications is smaller than that of red color. Hence, we have the term „below red color‟ or „Infrared‟. Infrared communication is used by military for surveillance, for vision in the darkness at night, tracking objects, etc. We use infrared communication whenever we use our remote controls to operate television sets, DVD players, etc. Weather forecasting & astronomy also make use of infrared communication.
Disadvantage:
i. The major disadvantage is that the sun generates radiation in the infrared band. This can cause a lot of interference with IR communication.
ii. Infrared signals cannot penetrate walls
iii. Large areas require multiple emitter panels, which will increase the cost of the system.