Allen-Bradley 2755-HDG-4 User Manual page 105

G–5
L
Laser
An acronym for Light Amplification by Stimulated Emission of
Radiation. The laser is an intense light source. Light from a laser is all
the same frequency, unlike the output of an incandescent bulb. Laser
light is typically coherent and has a high energy density.
Laser Diode
A gallium-arsenide semiconductor type of laser connected to a power
source to generate a laser beam. This laser type is a compact source of
coherent light.
P
Parameter
A variable that can have different values assigned to it.
Programming Mode
The state in which a scanner is configured for parameter values. See
SCANNING MODE.
Q
Quiet Zone
A clear space, containing no dark marks, which precedes the start
character of a bar code symbol and follows the stop character.
Publication 2755-6.2