Talk:RM4SCC
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The table shows alphas before numerics which is wrong. I've created a corrected version but don't know how to replace the original. My version: http://commons.wikimedia.org/wiki/Image:Rm4scc.svg
I've also written a GPL Perl routine to calculate the barcode text string. Can I add sample code to a page ?
Combination statement false[edit]
"An individual bar can be short, extend upwards, extend downwards, or extend both up and down. These four possibilities are reflected in the "four-state" name of the encoding. Each character is then made up of four of these bars. There are 36 possible combinations like this, and so 36 symbols:"
4 digits/bars which have each 4 states does not yield 36 combinations; it yields 256 combinations. The PO may only use 36 of them, but that's not what it says. Don't learn maths from Wikipedial, folks.
In fact, the patterns used by the code are restricted downwards from 256 by other required conditions. Each character sequence has to have 2 bars which extend upwards (either the upwards short bar, or the long bar) and, similarly, 2 bars which extend downwards. This gives 6 combinations of upward-extending bars, and 6 of downwards. 6*6=36 - that's where the 36 comes from.