Rockwell Automation 2755-G6-D Scanner with RS-232 Option User Manual

Page 98

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Glossary

G–3

hex: Abbreviated form of the word hexadecimal. See
hexadecimal.

hexadecimal: A base-16 numbering system that uses the
symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F.

horizontal bar code: A bar code or symbol presented in a
manner that its overall length dimension is parallel to the
horizon. The bars look like a picket fence.

Interleaved 2 of 5: A symbology in which characters are
paired together using bars to represent odd number char-
acters and spaces to represent even number characters.

ladder orientation: See vertical bar code.

modulus 43 check character: Used in Code 39 for data
security in addition to the built-in self-checking
characters. The check-character is the modulus 43 sum of
all of the character values in a given message and is the
last character in the code.

NAK: See negative acknowledgement.

negative acknowledgement (NAK): An ASCII control
character transmitted by a receiver as a negative response
to the sender.

orientation: The alignment of bars and spaces to the
scanner. Often referred to as vertical (ladder) or
horizontal (picket fence).

parity bit: An additional non-data bit attached to a binary
word to provide a check of the data integrity by making
the sum of the number of ones in a word always even
or odd.

picket fence code: See horizontal bar code.

scan: The search for a symbol or marks which are to be
optically recognized.

scan area: The area intended to contain a bar code
symbol.

scanner: A device that optically scans bar code symbols
and converts the optical information into digital or analog
form and sends it to a decoder.

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