Print device definitions are sets of functions and modes found in files with .PDF extensions that correspond to printers, plotters, and other peripherals.
The major functions of these definitions is to ensure that the job is printed properly and that the printer is left in a known state after completing a print job.
Printer functions (also referred to as control sequences, escape sequences or printer commands) give instructions to the printer. Print device definitions contain the necessary control sequences for such items as boldface type, underlining, rest, and other printer controls.
To define a printer's functions, you enter control sequences or printer commands into the print device database. To do this, you need the technical reference manual that came with your printer.
Print device definitions do not necessarily represent the full functionality of the printer. A print device definition can be modified to change the functions the machine will actually perform.