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

---

Maker Code

five digit after the flag in JAN code. It is given to the maker of products, import dealer or venders.
maker code is administrated by The Distribution System Research Institute / DCC; the Chamber of commerce & Industry gives the application services.

---

Margin

blank area of the bar. In this case, it is same as Quiet zone. (See Quiet Zone)

---

Module

The minimum unit of black/white bars in the multi-level barcode.
The modules compose an element, and the elements compose a character.

---

Modulus

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

---

MRD

<Minimum Reflection Difference> The difference of reflection ratios of white/black bars. It became to standard of printing color of USS, taking place of PCS.

in case the minimum element width < 1.016mm

Reflection Ratio of white bars (RL) 37.5 or more
Reflection Ratio of black bars (RD) 30.0 or less
MRD (RL - RD) might be 37.5 or more

in casse the minimum element width > 1.016mm

Reflection Ratio of white bars (RL) 25.0 or more
Reflection Ratio of black bars (RD) 30.0 or less
MRD(RL - RD) might be 20.0 or more

** Reflection Ratio is on the condition of red light in 660nm(nanometer = 1/100000000 m) wavelength. (See PCS)

---

Multi-level

One of the type of barcodes; having many types of width of black/white bars:
EAN, CODE-93, CODE-128, etc. (See binary level)