Glossary — Letter M

Maker Code / Margin / Module / Modulus / MRD / Multi-level

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Maker Code

The five digits following the flag in a JAN code. It is assigned to the maker of the products, the import dealer, or the vendor.
The maker code is administered by the Distribution System Research Institute / DCC; the Chamber of Commerce & Industry provides the application service.

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Margin

The blank area around the bars. In this context, it is the same as the Quiet zone. (See Quiet Zone)

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Module

The minimum unit of black/white bars in a multi-level barcode.
Modules make up an element, and elements make up a character.

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Modulus

Coefficient. This term is often used in the calculation of a checkdigit.

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MRD

Minimum Reflection Difference. The difference in reflection ratio between the white and black bars. It became the standard for printing color under USS, replacing PCS.

When the minimum element width is less than 1.016 mm:

Reflection ratio of white bars (RL): 37.5 or more
Reflection ratio of black bars (RD): 30.0 or less
MRD (RL - RD) should be 37.5 or more.

When the minimum element width is greater than 1.016 mm:

Reflection ratio of white bars (RL): 25.0 or more
Reflection ratio of black bars (RD): 30.0 or less
MRD (RL - RD) should be 20.0 or more.

** The reflection ratio is measured under red light at a 660 nm (nanometer = 1/1,000,000,000 m) wavelength. (See PCS)

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Multi-level

One of the barcode types; it uses many different widths of black/white bars:
EAN, CODE-93, CODE-128, etc. (See binary level)