Interested in infrared .........................................................................
For a brief moment in the evolution of the personal computer and the laptop,
there was the era of the infrared (IR)device. Everyone has been using this
technology for years. In fact, it is at the heart of one of the most important
essentials of modern life: the television remote control.
It appeared that infrared would be a natural medium for use in connecting
laptops and computers to printers and other devices, and to each other. You
may well find that a laptop or printer one or two generations old may have
infrared circuitry and a small red-filtered window for use in communication.
But IR had one big disadvantage: Devices had to be able to “see” each other
across the room. The signals might be able to bounce around a desk or off
the ceiling, but not through a door or wall. It was for that reason that IR was
quickly bypassed by WiFi, which can travel greater distances and penetrate
most walls.
Infrared communication for computers is an adaptation of the IEEE 802.11 stan-
dard, permitting interchange of information at about 1.6Mbps — if nothing is in
the way and the communication angle is no more than about 15 degrees off
center. IR is radiation of a frequency lower than visible light (below red light)
but higher than microwaves. The low end of the visible spectrum starts with
radiation that has a wavelength over about 700 nanometers. (A nanometer is
one-billionth of a meter.) Microwaves top out with a wavelength of 1mm and
range down to about 30cm. IR communications devices range in wavelength
from .85–.90 micrometer. (A micrometer is one-millionth of a meter.)
An infrared portis a specialized version of a standard serial port. Windows 98
and later include built-in support for IR ports, often using an industry standard
name of IrDA;if you’re still holding on to an old system running Windows 95,
that operating system can be updated to support IR if you can find the code
on the Microsoft web page or elsewhere on the Internet. Current versions of
Windows include an Infrared Wizard that configures the IR serial port and trou-
bleshoots communication between devices.
As I’ve said, IR has become a vestigial part on modern laptops and peripher-
als with the exception of a handful of cordless mice and keyboards. If you
have the capability and it works for you, that’s fine; if you’re buying a new
system, there is little reason not to use WiFi instead.
If an existing IR connection suddenly stops working, check the Device
Manager to see if it reports a conflict or a hardware failure. Consider re-
installing the device driver if it’s outdated or corrupted. If you are convinced
your IR circuitry has somehow failed, or if you need to add IR connectivity to
a laptop to communicate with another device, the simplest and least expensive
solution is to purchase a USB device that adds an IR channel; such hardware
is available for as little as $20.
Chapter 14: Feeling Up In the Air 223