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Browse Prior Art Database

Word Processing BAR Code

IP.com Disclosure Number: IPCOM000046163D
Original Publication Date: 1983-Jun-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 5 page(s) / 37K

Publishing Venue

IBM

Related People

Nielson, MC: AUTHOR

Abstract

This article describes a binary code useful for word processing applications and usable on impact and nonimpact printers. The code is insensitive to low-frequency velocity variations so that it can be scanned by hand or machine.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 31% of the total text.

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Word Processing BAR Code

This article describes a binary code useful for word processing applications and usable on impact and nonimpact printers. The code is insensitive to low- frequency velocity variations so that it can be scanned by hand or machine.

Certain terms used in this description are defined below.

BAR CODE: A binary encoding on printed media using two contrasting colors, usually black and white, containing information in one dimension only.

MODULE: The minimum dimension that can be specified for the code, defining the code resolution (in modules per unit distance).

BAR: One or more modules of the same color in a contiguous group.

MARK: A printed bar in the color of the ink.

SPACE: An unprinted bar in the color of the background (paper).

BIT CODES: Bar codes intended to be printed and decoded on a bit basis.

CHARACTER CODES: Bar codes intended to be printed and decoded using a fixed number of modules. (Character codes have the advantage that a printer can print them as it would any other character font.)

WIDTH DECODING: A decoding process measuring the relative widths of bars. (Systematic variations, such as marks that are consistently too wide, adversely affect the performance of width decoding.)

LIKE-TRANSITION DECODING: A decoding process measuring the widths of adjacent mark-space and space-mark pairs. Distances are always measured from a mark to a mark or from a space to a space, hence the designation like- transition.

The two most common classes, encompassing most of the codes defined to date, are binary bar width modulation codes (BBWM) and (N,K) codes.

BBWM codes are characterized by one or two bar widths and one or two space widths. BBWM codes are well suited to bit codes, but they have also been used for character codes. Depending upon the coding rule chosen, BBWM codes can be either width or like-transition decoded.

The other class of common bar codes, the (N,K) codes, are character codes. N is the number of modules in the character having K marks and K spaces. The (N,K) codes are like-transition decodable and so have good insensitivity to systematic variations. An example of an (N,K) code is the UPC (Universal Product Code) which is a (7,2) code, i.e., the UPC character is composed of 7 modules with two marks and two spaces.

The word processing bar code (WPBC) to be described has the

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following features:

(1) The code is applicable to impact printers, e.g.,

daisy wheel, and nonimpact printers, e.g., ink

jet;

(2) The code is velocity independent so it is hand- or

machine- scannable;

(3) The bar code is bidirectionally readable, short

beginning and end sequences being used to provide

unique decodability independent from scan

direction;

(4) There are at least 63 unique code points for the

upper and lower case alphabetics, the decimal

numbers, and one escape code, with control and

special codes being encoded using the escape

character; and

(5) The average density (number of symbols per unit

area) o...