In essence, the PPA protocol moves the low-level processing of the data to the host computer rather than the printer. However, in practice the printer was often as expensive as more capable printers and HP has since discontinued the use of PPA in favour of returning to PCL3e in their latest USB-based printers. This project is a testament to open source persistence to develop a workable solution for a proprietary platform despite the original manufacturer being extremely unhelpful.
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