If your new printer's data stream differs significantly from one of the numerous printer data streams currently handled by the operating system, you must define a new backend formatter. Adding a new formatter does not require the addition of a new backend. Instead, all you typically need are modifications to the formatter commands associated with that printer under the supervision of the existing printer backend. If a new backend is required, see "Printer Backend Overview for Programming" in AIX Version 4.3 Guide to Printers and Printing.
Subroutines for Printer Formatters.