Glossary — Letter C

CCD / Cell / Character / Character Density / Character Set / Checkdigit / Code Type / Continuous / CPI

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CCD

Charge Coupled Diode. A memory device which converts light into an electric signal using a matrix of many particles on a silicon base. Used for barcode recognition by hand-held scanners.

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Cell

This term is used as the minimum unit of a 2-dimensional symbol.

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Character

The combination of black/white bars used to express each letter, numeral, mark, etc.

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Character Density

The maximum number of readable characters in a given length. (See CPI)

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Character Set

The type of characters that a barcode can express.
There are several character sets, such as numerics-only, numerics and marks, or numerics, letters and marks including full ASCII control codes — these vary according to the type of barcode.

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Checkdigit

A checking digit used to avoid misreadings.
When a character is recognized incorrectly as another, due to a void or spot, the checkdigit, if present, helps detect the error.

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Code Type

There are two code types in barcode: Continuous type and Discrete type. Continuous type includes EAN, Interleaved 2 of 5, CODE-93 and CODE-128. Its character density is high, but it is more difficult to print. Discrete type includes CODABAR, CODE-39, Straight 2 of 5, etc. Its character density is comparatively low, but it is easier to print, so it is often produced by personal printers and used for number printing. (See continuous, discrete)

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Continuous

Continuous type is one of the code types of barcode.
The last space character has meaning, functioning as a white bar. (See Discrete code type)

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CPI

Characters Per Inch. The maximum number of characters of readable size in 1 inch. (See character density)