The symbol comprises 2 to 16 rows, each of which contain the following elements:

• Leading quiet zone

• Start character

• Guard bar

• Five symbol characters

• Stop character

• Trailing quiet zone

Each Code 16K row contains five ASCII characters. If fewer than five characters are encoded, the row is filled with placeholder characters. Rows are separated by a horizontal separator bar.

The separator bars on the bottom and top of the symbol extend to the ends of the leading and trailing quiet zones for the symbol. For this reason, they are longer than the separator bars that are inside the symbol.

Up to 107 Code 16K symbols can be stacked, which enables up to 8,025 ASCII characters or 16,050 numeric characters to be encoded.

This symbology supports the 128 lower ASCII characters and the full 256-character extended ASCII set when the FNC4 shift character is used.

Because Code 16K uses Code 128, there are three character code sets (A, B, and C), which are summarized as follows:

• Code Set A: Includes all numeric values (0-9), uppercase alphabetic characters (A-Z), punctuation marks, eleven special characters, and "control" characters (ASCII values 00 through 95).

• Code Set B: Includes all numeric values (0-9), uppercase and lowercase alphabetic characters (A-Z, a-z), punctuation marks, and eleven special characters (ASCII values 32 through 127).

• Code Set C: Includes all numeric digit pairs from 00 through 99 and seven special characters. This code set is numeric-only, but any one character actually represents two digits.

It is possible for one symbol to switch between the different character sets.

Code 16K supports the following function characters: 

• FNC 1 - Symbol type identifier

• FNC 2 - Message append

• FNC 3 - Initialize

• FNC 4 - Extended ASCII mode

Code 16K contains two mandatory check digits that are based on the modulo 107 algorithm.

The minimum X dimension of Code 16K is 7.5 mils. The height of each row must be at least 8X, where "X" is the current X dimension. The leading quiet zone should be at least 10X wide and the trailing quiet zone at least 1X wide.