HP Support links for PCL
- Printers supported by HP Universal Print Driver (UPD)
- Differences between PCL 3 and PCL 5/6 (https://support.hp.com/in-en/document/c00068221)
Other useful PCL links
Gracious thanks to Karthik Punja of Robonik India for sharing these useful links:
- https://www.pclviewer.com/resources/reference/
- https://github.com/michaelknigge/pclparaphernalia/blob/master/README.md
PCL Paraphernalia is a free utility which provides a small collection of tools of use to technicians supporting printing on PCL5 and PCL6 printers.
- http://www.undocprint.org/start
Contains basic information for multiple printing protocols. Has not been updated since 2011 but may still be informative.
- https://github.com/OpenPrinting/cups-filters/tree/master/filter
This section of the github repository contains c code for PCL and other printer languages