OCR-A is the font used for the ISBNs on books; and OCR-B is used for the human-readable digits on UPC/EAN bar codes. A book with a standard bar code label uses both.
I translated existing Metafont sources to MetaType1 to create the enhanced TrueType, PostScript, and OpenType versions included in this package.
They are available for free use, including in commercial applications; my own contributions are public domain, and others have licensed their copyright claims.