The last factor of font selection is human readable text. The human
readable text can be added using a text font. For convenience,
we create fonts with human readable text built-in. It is easy to
identify human-readable fonts - these fonts with names ending with a trailing letter
A. Therefore,
MRV Code39M produce barcodes only, whereas
MRV Code39MA produces barcodes with human readable.
Except this difference, the two fonts are identical.