I have an ancient fax device with a printer interface that only accepts postscript level 1 documents formatted in a specific way. I only have access to this printer over the lpd:// protocol.

I have some old documents from our previous system that work fine on our Unix machines, but they are altered somehow by CUPS when I use lp on our Linux system. The PDF files that end up in the print queue are significantly modified versions of the original, and although they still render in ghostscript, they don't do anything on the printer.

I'm wondering if there's a way to tell CUPS "don't process this, just send it to the printer without modification", or whether there's a lpd client or procedure I could try?