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Infrared radiation (IR) or the term infrared
alone refers to energy in the region of the electromagnetic
radiation spectrum at wavelengths longer than those of visible
light, but shorter than those of radio waves. Correspondingly,
the frequencies of IR are higher than those of microwaves,
but lower than those of visible light.
Scientists divide the IR spectrum into three
regions. The wavelengths are specified in microns (symbolized
µ, where 1 µ = 10-6 meter) or in nanometers
(abbreviated nm, where 1 nm = 10-9 meter = 0.001 µ).
The near IR band contains energy in the range of wavelengths
closest to the visible, from approximately 0.750 to 1.300
µ (750 to 1300 nm). The intermediate IR band (also
called the middle IR band) consists of energy in the range
1.300 to 3.000 µ (1300 to 3000 nm). The far IR band
extends from 2.000 to 14.000 µ (3000 nm to 1.4000
x 104 nm).
Infrared is used in a variety of wireless
communications, monitoring, and control applications. A
few of the applications include home-entertainment remote-control
boxes, wireless local area networks, links between notebook
computers and desktop computers, cordless modems, intrusion
detectors, motion detectors, and fire sensors
Universal Mobile Telecommunications System
(UMTS) -- a broadband, packet-based system offering a consistent
set of services to mobile computer and phone users no matter
where they are located in the world
Wireless Application Protocol (WAP) -- a
set of communication protocols to standardize the way that
wireless devices, such as cellular telephones and radio
transceivers, can be used for Internet access
i-Mode -- the world's first "smart
phone" for Web browsing, first introduced in Japan;
provides color and video over telephone sets
Wireless can be divided into:
fixed wireless -- the operation of wireless devices or systems
in homes and offices, and in particular, equipment connected
to the Internet via specialized modems
Mobile wireless -- the use of wireless devices
or systems aboard motorized, moving vehicles; examples include
the automotive cell phone and PCS (personal communications
services)
Portable wireless -- the operation of autonomous,
battery-powered wireless devices or systems outside the
office, home, or vehicle; examples include handheld cell
phones and PCS units
IR wireless -- the use of devices that convey
data via IR (infrared) radiation; employed in certain limited-range
communications and control systems
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