5IrDA (Infrared Data Association) is an industry-sponsored organization set up in 1993 to create international standards for the hardware and software used in infrared communication links. In this special form of radio transmission, a focused ray of light in the infrared frequency spectrum, measured in terahertz, or trillions of hertz (cycles per second), is modulated with information and sent from a transmitter to a receiver over a relatively short distance. Infrared radiation (IR) is the same technology used to control a TV set with a remote control.
Infrared data communication is playing an important role in wireless data communication due to the popularity of laptop computers, personal digital assistants (PDAs), digital cameras, mobile telephones, pagers, and other devices. Among existing uses or likely possibilities are:
- Sending a document from your notebook computer to a printer
- Exchanging business cards between handheld PCs
- Coordinating schedules and telephone books between your desktop and notebook computers
- Sending faxes from your notebook computer to a distant fax machine through a public telephone
- Digital cameras that can beam images into your computer
Infrared communication involves a transceiver (a combination transmitter and receiver) in both devices that communicate. Special microchips provide this capability. In addition, one or both devices may require special software so that the communication can by synchronized. An example is the special support for IR in Microsoft's Windows 95 operating system. In the IrDA-1.1 standard, the maximum data size that may be transmitted is 2048 bytes and the maximum transmission rate is 4 Mbps.
IR can be also be used for somewhat longer interconnections and is a possibility for interconnections within local area networks. The maximum effective distance is somewhat under 1.5 miles and the maximum projected bandwidth is 16 megabits per second. Since IR is line-of-sight light transmission, it is sensitive to fog and other atmospheric conditions.