Some Bar codes require a Start and stop code at the beginning and end of the string. It is not enough to just format the string with the barcode font. you need to use a formula to add the required start and stop codes ... and sometimes a "check Digit" as well. They are all a little different and have their own peculiarities Even if the code looks correct you should verify that it is working correctly with a bar code scanner to confirm that it actually works.
for example 3of9 also know as C39 or code 39 requires a an asterisk ( * ) symbol at the beginning and end of each string to be read.
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