On Thu, 2022-06-23 at 13:15 -0400, Jon LaBadie wrote:
I have a 10+ year old Ricoh 3500N color laser that claims to
accept PDF files. It is on my lan as host "R3500", a postscript
printer and connects using CUPS and an IPP socket.
I never considered whether the cups drivers were converting my
PDF files to PS before transmitting.
In my case, I just tried sneakernetting PDF files to it over USB
(mine's a similarly vintage HP LaserJet P3015).
In the past, I remember CUPS was rather good at detecting whether it
was being sent prepared data that could go direct to the printer, or it
was receiving Linux internal printing instructions that had to go
through the driver. Though, as far as I knew, that was detecting
print-ready PostScript, or the printers own page language.
There was also the option of manually setting up a RAW queue, where you
set print-ready data to it, and it just passed it along to the printer.
So today I tried using netcat to send PDF files directly to the
printer
$ nc R3500 {port_number} < {pdf_file}
When I used port 631 (IPP) I got HTTP errors (400 BAD REQEUEST)
But when I used port 9100 (JetDirect) 5 different pdf files of
varying complexity printed properly.
That makes sense. The IPP port simply expecting the usual data, it's
special port may be more versatile.
Out of curiosity, if you pipe a PostScript file through to either port,
does it handle that? (Assuming the printer supports that format, in
the first place.)
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