The symbol comprises two to eight rows that contain the following elements:

• Leading quiet zone

• Row start pattern

• Four symbol characters that encode eight ASCII characters, the last of which is a row check character

• Row stop pattern

• Trailing quiet zone

The data input is encoded in exactly 18 bars and 17 spaces per row. Placeholder characters are used to fill out rows that have fewer than eight data 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.

The start pattern is a one-module-wide (1X) bar followed by a 1X space, and the stop pattern is a 4X bar.

This symbology supports the full 128-character ASCII set.

Code 49 contains a row check digit for each row and a symbol check digit for the overall symbol. Row check digits are based on the modulo 49 algorithm, and symbol check digits are based on the modulo 2401 algorithm.

Code 49 has a fixed width of 70 modules (70X). The height of each row must be at least 8X. The leading quiet zone should be at least 10X wide and the trailing quiet zone at least 1X wide.