From LQWiki

Infrared

Not strictly speaking a bus, it allows the transmission of data as Invisible light, similar to a remote control for a house hold appliance.

the core IrDA protocol layers including:

   * The infrared physical layer
   * Controllers, drivers and framers
   * IrLAP: The IrDA Link Access Protocol ([Linux])
   * IrLMP: The IrDA Link Management Protocol
   * TinyTP: The IrDA Tiny Transport Protocol
   * IAS: The IrDA Information Access Service
   * IrDA Lite strategies

A description of important session layer protocols including:

   * IrCOMM and IrLPT: Legacy support for serial and parallel communications ([Linux] modules)
   * IrOBEX: IrDA Object Exchange ([Linux] applications)
   * IrFM: Infrared Financial Message exchange

Good explanation of IR can be found at gnokii-IrDA-Linux