Pharmacode, also known as Pharmaceutical Binary Code, is a barcode

Barcode

A barcode is an optical machine-readable representation of data, which shows data about the object to which it attaches. Originally barcodes represented data by varying the widths and spacings of parallel lines, and may be referred to as linear or 1 dimensional . Later they evolved into rectangles,...

 standard, used in the pharmaceutical industry as a packing control system. It is designed to be readable despite printing errors. It can be printed in multiple colors as a check to ensure that the remainder of the packaging (which the pharmaceutical company must print to protect itself from legal liability) is correctly printed.

Encoding

Pharmacode can represent only a single integer

Integer

The integers are formed by the natural numbers together with the negatives of the non-zero natural numbers .They are known as Positive and Negative Integers respectively...

from 3 to 131070. Unlike other commonly used one-dimensional barcode schemes, pharmacode does not store the data in a form corresponding to the human-readable digits; the number is encoded in binary, rather than decimal. Pharmacode is read from right to left, also in left to right (if omnidirectional scanner): with as the bar position starting at 0 on the right, each narrow bar adds to the value and each wide bar adds . The minimum barcode is 2 bars and the maximum 16, so the smallest number that could be encoded is 3 (2 narrow bars) and the biggest is 131070 (16 wide bars).
It represent colors which are on the label