Infrared radiation is the region of the electromagnetic spectrum between microwaves and visible light. In infrared communication an LED transmits the infrared signal as bursts of non-visible light. At the receiving end a photodiode or photoreceptor detects and captures the light pulses, which are then processed to retrieve the information they contain. Some common applications of infrared technology are listed below.

Augmentative communication devices
Car locking systems
Computers
a. Mouse
b. Keyboards
c. Floppy disk drives
d. Printers

Emergency response systems
Environmental control systems
a. Windows
b. Doors
c. Lights
d. Curtains
e. Beds
f. Radios

Headphones
Home security systems
Navigation systems
Signage
Telephones
TVs, VCRs, CD players, stereos
Toys
Infrared technology offers several important advantages as a form of wireless communication. Advantages and disadvantages of IR are first presented, followed by a comparative listing of radio frequency (RF) advantages and disadvantages.




IR Advantages:
Low power requirements: therefore ideal for laptops, telephones, personal digital assistants
Low circuitry costs: $2-$5 for the entire coding/decoding circuitry
Simple circuitry: no special or proprietary hardware is required, can be incorporated into the integrated circuit of a product
Higher security: directionality of the beam helps ensure that data isn't leaked or spilled to nearby devices as it's transmitted
Portable
Few international regulatory constraints: IrDA (Infrared Data Association) functional devices will ideally be usable by international travelers, no matter where they may be
High noise immunity: not as likely to have interference from signals from other devices



IR Disadvantages:
Line of sight: transmitters and receivers must be almost directly aligned (i.e. able to see each other) to communicate
Blocked by common materials: people, walls, plants, etc. can block transmission
Short range: performance drops off with longer distances
Light, weather sensitive: direct sunlight, rain, fog, dust, pollution can affect transmission
Speed: data rate transmission is lower than typical wired transmission

wht about bluetooth technology???

Bluetooth I think, is so much better than Infared for short range communication. IR technology is too "weak" and it also requires a line of sight (that is, the IR ports need to be facing each other directly in order for it to work)