Linux Unwired

Chapter 8. Infrared

Infrared is a legacy technology that won’t die any time soon. Sure, it has lousy range and can be a hassle to set up, but sometimes, it’s the only common communications medium between your Linux box and something you want to talk to.

If you have ever used a remote control, you have used infrared technology. Infrared is a wireless communication technology that makes use of the invisible spectrum of light that is just beyond red in the visible spectrum. It’s suitable for applications that require short-range, point-to-point data transfer. Because it uses light, line of sight is a prerequisite for using infrared. Despite this limitation, infrared is widely used in household equipment and is increasingly popular in devices such as digital cameras, PDAs, and notebook computers.

Founded in 1993 as a nonprofit organization, the Infrared Data Association (IrDA) is an international organization that creates and promotes interoperable, low-cost infrared data interconnection standards that allow users to transfer data from one device to another. The Infrared Data Association standards support a broad range of appliances, computing, and communications devices.

Tip

The term IrDA is typically used to refer to the protocols for infrared communications, not exclusively to the nonprofit body.

There are currently four versions of IrDA; their differences are mainly in the transfer speed:

Serial Infrared (SIR)

The original standard with a transfer speed of up to 115 kbps

Medium Infrared ...