Tally Genicom Matrix Printer manual Ansi Bar Codes

Chapter 3. ANSI Bar Codes

This chapter describes the characteristics and lists ANSI control sequences for 23 resident bar code styles. You have to be in ANSI emulation to print the resident bar codes. You can adjust various bar code attributes including rotation, height, print density, status of the human-readable line, and element widths. Subject to some constraints based on style and rotation, the human- readable font is also selectable. For some styles, the printer will calculate checksum characters for you.

To print a bar code symbol, you need to:

1)Set the printer to ANSI emulation.

2)Send the escape sequence to set the user-adjustable attributes. Always do this at least once.

3)Send the control sequence to turn on bar code.

4)Send the ASCII representation of symbol data you want to encode.

5)Send the control sequence to turn off bar code.

6)Send a line terminator at some point thereafter.

In bar code parlance, a module is the narrowest nominal width of measure, while an element is a single bar or space. A character is a group of elements that represents a number, letter, or punctuation mark. A symbol is a group of characters that can stand alone in terms of being interpreted by the reader. A symbol always comprises one or more data characters framed by white spaces known as quiet zones. The symbol frame almost always includes start and stop characters. Depending on the style, some bar code symbols can also include check characters, center characters, and guard bars.

Among printers that generate bar codes internally and that also support any user-adjustment of bar code widths, some enable the specification of module width, while others, such as this one, enable the adjustment of element widths. From the programmer's point of view, adjustable module widths tend to guarantee that the ratio among element widths remains correct, while adjustable element widths afford more flexibility.

When we ship the printer, the ratios among element widths in a given bar code style are within generic specifications for that style. You can restore these default element widths by performing an initial setup (ISU) as described in the User's manual. Since this printer lets you specify element widths independently of each other, it is possible to print bar codes that are outside of generic specifications, or outside of the limits of your particular reading system, or both. You need to know the requirements of your system before you program your printer.

Bar codes printed with this printer are suitable for readers designed for low- or medium-density bar code symbols. Avoid readers with apertures smaller than 7 mils. If bar codes are to be read with an infrared reader, then you must use a special carbon ribbon.

The examples given in this section use the Code 3-of-9 format.

7265 Programmer’s Manual	33
Copyright © 2004 TallyGenicom	Chapter 3 ANSI Bar Codes