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Infrared Data Association (IrDA)

IrDA is a very short-range example of free space optical communication.

IrDA interfaces are used in palmtop computers, mobile phones, and laptop computers (most laptops and phones also offer Bluetooth, but it is now becoming more common for Bluetooth to simply replace IrDA in new versions of products).
IrDA specifications include IrPHY, IrLAP, IrLMP, IrCOMM, Tiny TP, IrOBEX, IrLAN and IrSimple. IrDA has now produced another standard, IrFM, for Infrared financial messaging (i.e., for making payments) also known as "Point & Pay".

Implementation Related

>> Siemens IRM3100/3105 Transceiver Application Example