Tuesday, July 3, 2018

Code 39 intercharacter gap

I was fiddling with my barcode scanner and an old UPS barcode.

It was obviously code 39 but when I made my own version of it using one of the online web barcode generators, the bars didn't look the same. The pattern was very similar but subtly different.

What I discovered is that the intercharacter gap is wide instead of narrow. According to https://en.wikipedia.org/wiki/Code_39, "Characters are separated by an additional narrow space."


I wonder if a larger intercharacter gap made it easier to decode years ago.


So here's the original barcode with a freshly generated version underneath for comparison.