Glossary of Terms
MS-850 Raster Scanner User’s Manual
A-25
Appe
ndices
trol the orderly flow of information between linked devices.
Quiet Zones
. Specified “clear” (nonprinted) areas immediately before and after the
bar code symbol. The area is usually white (for black and white bar code) and at
least 10 times the width of the narrowest bar, as measured in thousands of an inch.
The zones can be other than white as long as their densities remain consistent and
they have the required contrast relative to the bars.
RAM
. (Random Access Memory) Memory that is lost after power is recycled to the
unit.
Read Cycle
. A programmed period of time or condition during which the scanner
will accept bar code label input.
Raster Height
(RH) is the distance between the extremities of the scan lines as
shown in the raster image. Raster height is generally dictated by the application
(range and label placement). Other factors being equal, the greater the raster
height, the fewer scan lines available for given label.
Read Range
. The distances in which a label can be reliably read, as measured from
the front of the scanner. See “Depth of Field.”
Relay Driver.
A TTL signal sent by the scanner. The output is determined by the
relay driver selection (by operational command).
ROM
. (Read Only Memory) Memory that cannot be changed.
Scanner
. A scanning device that is comprised of a scan head and a decoder inte-
grated in one package.
Scan Rate
(SR) The number of scans per second that a given scanner is capable of
casting.
Scan Width
(SW) is the width across the scan beam at a given distance from the
scanner in which a label can be read.
Serial Commands
. Online data strings (including configuration and operations)
from a host or other terminal to the scanner, that are always preceded by a < left
angle bracket symbol and followed by a > right angle bracket symbol.
Serial Configuration
(Host Configuration). Serial command specifically for chang-
ing configuration and distinguished from operational command by the fact that they
modify the non-volatile for power up configuration.
Skew
. Label (or scanner) rotation around the center of the skew axis.
Specular Reflection
. The direct, mirror-like reflection of laser light back to the
scanner, causing over-light saturation. For the MS-850 scanner, specular reflection is
avoided by skewing or pitching labels slightly.
Successive Scanner
. Linked to the primary or preceding scanner in a daisy chain
mode via its aux port to relay bar code data to the host. See “Daisy Chain.”
Sweep Rate
(SwR) is the number of passes per second, up or down, describing the
raster image.
Symbology
. A set of bar code symbols, such as Code 39 or Code 128, that have
