Consumer IR

Consumer IR, or CIR, refers to a wide variety of infrared remote control protocols. The term is often used to refer to an infrared port on a PDA, laptop, or other computer that supports CIR as well as other protocols such as IrDA. Since the Consumer IR protocols are for the most part not standardized, computers and universal remotes often memorize a bit stream, possibly with compression and possibly without determining the actual bit rate, and play it back. Similarities between remotes are often largely the accidental result of the finite selection of infrared encoder/decoder chips (though now microcontrollers are also used) and IR receiver modules or imitation of the older chips rather than by design. Manufacturers of consumer appliances often do reuse the same protocol on many similar devices, though for each manufacturer and device type there are usually multiple protocols in use (just look at the code listings for any universal remote).
See more at Wikipedia.org...