IR 
infrared 
In infrared data communication, a focused ray of light in the infrared frequency spectrum is sent from a transmitter to a receiver over a relatively short distance--the same technology used to control a TV set with a remote control. This technology still plays a role in wireless data communication among PCs, notebook computers, PDAs, digital cameras, mobile telephones, pagers, and other devices. Because it requires a line-of-sight connection between the transmitter and receiver, however, it has limitations compared to wireless technologies such as Bluetooth, which are rapidly taking over IR's duties.