CUPS Also Uses PPDs for Non-PostScript Printers
CUPS also uses specially crafted PPDs to handle non-PostScript printers. These PPDs are usually not available
from the vendors (and no, you can't just take the PPD of a PostScript printer with the same model name and
hope it works for the non-PostScript version too). To understand how these PPDs work for non-PS printers, we
first need to dive deeply into the CUPS filtering and file format conversion architecture. Stay tuned.