Rockwell Automation 2755 Enhanced Decoder Series B - Manual (Page 348)

Glossary G–7
Publication 2755-833
output counter
A counter that is associated with each output condition. The counter
increments by 1 each time the condition occurs.
overhead
The fixed number of characters required for start, stop and checking
in a given symbol. For example, a symbol requiring a start/stop and
two check characters contains four characters of overhead. To
encode three characters of data, seven characters are required.
P
PCCC
Acronym for Programmable Controller Communications
Commands. A set of commands used to communicate with
Allen-Bradley programmable controllers.
percent good reads
The number of successful reads per 100 attempts to read a particular
symbol.
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
A code pattern in which the direction of travel of the symbol is
perpendicular to the bars and spaces of the code.
R
RS232, RS422, RS485
Electrical standards for data communications.
read
An output condition in which an entire package is correctly decoded.
In the continuous decode modes, read and valid read (see valid read)
have the same meaning.
S
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.