This software creates output using the PPA (printer performance architecture) protocol. This protocol is used by some HP "Windows-only" printers (so called GDI), including the HP Deskjet 820C series, the HP DeskJet 720 series, and the HP DeskJet 1000 series. Currently only black-and-white printing is supported right now.
A short description how to use ppa with apsfilter is given in the directory /usr/doc/packages/ppa/.
For full information on the PPA protocol and this software, visit http://www.rpi.edu/~normat/technical/ppa/ .