Do you know if this card is supported by the software RIP 'TScript'? I have tested TScript with a RS422 to parallel port adaptor years ago. The PCL emulation is done within the software, which sets up a virtual PostScript printer in an AppleTalk network and translates PostScript jobs into appropriate input for the printer chosen within the TScript preferences. A dozen years ago I used this to produce best possible graphics and typo output with a HP DeskWriter (a lot better than with the original HP DeskJet driver or Chucks printer driver). With a working copy of 'TScript' you might be able to improve the output quality of many printers that can be connected to your Mac, extending the abilities of their native drivers by far (as are StyleWriter Printers, non-PostScript parallel port laser printers, ALPS SCSI high-end thermo sublimation colour printers etc.) Any printer supported by TScript benefits from additional PostScript support and additional network accessibility.

Btw: It is a nice liberation project to use any Mac with decent power as a TScript print server. Once set up, it can run without VRAM and without any peripherals except for the printer, connected local or via network.