Wireless IR is the use of wireless technology in devices or systems that transmit data through infrared (IR) radiation. Infrared is electromagnetic energy at wavelengths or wavelengths somewhat longer than those of red light. The shortest wavelength IR boundaries are visiblered in the electromagnetic radiation spectrum, the longest wavelength IR boundary radio waves.
Some engineers consider IR technology as a sub-specialty of optical technology. The hardware is similar, and the two forms of energy behave in the same way. But, strictly speaking, "optical" refers to visible electromagnetic radiation, while "infrared" is invisible to the unaided eye. To compound the confusion, IR is sometimes referred to as "infrared light".
Wireless IR is used for short- and medium-range communications and control. Some systems operate in line-of-sight mode; this means that it must be a straight line without visual obstructions through the space between the transmitter (source) and the receiver (destination). Other systems operate in fuzzy mode, also called scatter mode. This type of system can work when the origin and destination are not directly visible to each other. An example is a television control box. The box does not have to be marked directly on the set, although the box must be in the same room as the set, or just outside the room with the door open.
IR wireless technology is used in intrusion detectors; home entertainment control units; robot control systems; medium and linear range laser communications; wireless microphones, headphones, modems and printers and other peripherals.