Barcodewiz 128 Code All 128

Using the example above, an A would be depicted with the pattern 10100011000, or as widths 111323 in the tables below.

Barcodewiz 128 Code All 128

It can encode all 128 characters of ASCII and, by use of an extension symbol (FNC4), the Latin-1 characters defined in ISOIEC 8859-1.

Each symbol consists of three black bars and three white spaces of varying widths.

Each bar and space is 1 to 4 modules wide, and the symbols are fixed width: the sum of the widths of the three black bars and three white bars is 11 modules.

When the stop pattern is read left-to-right (the usual case), the stop symbol (followed by a 2-module bar) is recognized.

When the stop pattern is read right-to-left, the reverse stop symbol (followed by a 2-module bar) is recognized.

A scanner seeing the reverse stop symbol then knows it must skip the 2-module bar and read the rest of the barcode in reverse.

To represent all 128 ASCII values, it shifts among three code sets (A, B, C).

The initial subset is selected by using the appropriate start symbol.

Within each code set, some of the 103 data code points are reserved for shifting to one of the other two code sets.

The shifts are done using code points 98 and 99 in code sets A and B, 100 in code sets A and C and 101 in code sets B and C to switch between them).

Each bar or space is 1, 2, 3 or 4 units wide, the sum of the widths of bars must be even (4, 6 or 8 units), the sum of the widths of the spaces must be odd (3, 5 or 7 units), and total 11 units per symbol.

For instance, encoding the ASCII character 0 can be viewed as 10011101100, where a sequence of 1s is a bar and a sequence of 0s is a space.

Three 1s in sequence (111) indicates a bar three times as thick as a single 1 bar.

Two of the symbols are used for stop (end-of-barcode) indication, stop and reverse stop.

The two stop symbols are special because they are always followed by a 2-unit bar, forming a 13-unit long stop pattern.

Reading the stop pattern left to right is the stop symbol (followed by a 2-unit bar), and reading the stop pattern right to left is the reverse stop symbol (followed by a 2-unit bar).

It is calculated by summing the start code value to the products of each symbols value multiplied by its position in the barcode string.

The remainder is then converted back to one of the 103 non-delimiter symbols (following the instructions given below ) and appended to the barcode, immediately before the stop symbol.

The checksum is computed over the symbol values, without regard for which code set is active at the time.

For instance the code set C value 33 and the code set B value A are both considered to be a Code 128 value of 33, and the check digit is computed based on the value of 33 times the symbols position within the barcode.

Between the double FNC4s, a single FNC4 will be used to denote that the following character will be standard ASCII.

In barcode fonts, the final bar is generally combined with the stop symbol to make a wider stop pattern.