hpnpf	A replacement backend for the CUPS socket backend
=========================================================

DESCRIPTION

This backend is based on HP's hpnpf utility (the sources of which have been freely
availabel until 1992) and has been extended to safely report the backchannel messages
from a JetDierect driven HP printer and - for PostScript printers only - to use
the TBCP (Tagged Binary Communications Protocol) as defined by Adobe.

The program can be run either as a CUPS backend or as a standalone utility, depending
on the name it is called by:

- if the name it is called with contains one of the strings '://' or 'backend/hpnpf'
  (the latter for use with the CUPS backend test utility), it runs as a CUPS
  backend, following the CUPS backend calling and input/output conventions.
- otherwise, it runs as a standalone utility and accepts additional switches.


INSTALLATION

Unzip and untar the file hpnpf.tgz into a suitable directory.
Within that directory, on SYSV UNIXes, run "make hpnpf", on Linux systems, 
run "make -f linux.mak hpnpf". (Don't try to make hpnptyd, this won't succeed.)
On systems which do not/no longer support the good old varargs stuff but
require the use of the new stdarg approach for variable argument lists,
use 
	make -f linux_std.mak
or
	make -f sysv_std.mak
for SYSV systems.

For CUPS use, copy the compiled binary hpnpf to the CUPS backend directory, 
usually /usr/lib/cups/backend.
For standalone use, copy the binary to e.g. /usr/local/bin.


CUPS USAGE

When configuring a CUPS printer for using this backend, the URI syntyx is much the same
as for the standard socket backend:
	hpnpf://printername:port
where port usually is 9100.
To enable TBCP, append the string "/TBCP" to the URI, as:
	hpnpf://printername:port/TBCP

The backend writes information to a printer specific log file,
	/var/log/cups/status_log.printername
For each job printed, an identification line like
	INFO: [Mon Sep 11 11:08:08 2000] HPDIACOS.0001.SRZ0.11486.PS (1999)
containing the current date, the job ID (much like the standard backend) and the job number.
An info message like
	INFO: Printing: HPDIACOS.0001.SRZ0.11486.PS
is written to stderr and thus captured by cupsd and available as status message.
Any PostScript error messages are logged like:
	INFO: %%[ Error: rangecheck; OffendingCommand: getinterval ]%%
These errors are passed as info messages to cupsd as:
	INFO: HPDIACOS.0001.SRZ0.11486.PS | %%[ Error: rangecheck; OffendingCommand: getinterval ]%%
and thus available as the printer's status message.
If no error occurred, a completion message is passed to cupsd like:
	INFO: Printed: HPDIACOS.0001.SRZ0.11486.PS

For debugging, you may append "-D" to the device-URI. In this case, any PJL commands and replies
are logged to the printer specific status log file as specified above, and 
debugging messages from hpnpf are written to /var/log/cups/printername.log.


STANDALONE USAGE

Called without any parameters the following usage message is printed to stderr:

usage: hpnpf -x periph [-c port] [-nNPrRSTvwW] [-p port] [-s statusfile] [-l logfile] file ...
	-n	(PLC only) map LF->CRLF, FF->CRFF
	-N	map LF->CRLF physically
	-P	(PostScript only) print banner page
	-r	run in relay mode
	-R	do no retries if connection fails
	-S	delete all CRs
	-T	(PostScript only) use TBCP (Tagged Binary Communcations Protocol)
	-v	verbose mode
	-w	wait for the job to be completed
	-W	as -w, additionally display all PJL commands and replies
	-c port	control port number (for relay mode only)
	-x periph	name or IP addr of printer
	-p port	port number to connect with
	-s statusfile	file to which status messages are written; default: stdout
	-l logfile	file to which logging messages are written (- : stderr)
	file ...	files to be printed; read from stdin if no files are given

The -w switch enables the logging of the PostScript messages, the -W switch additionally
logs the PJL commands and replies, -T enables the TBCP protocol. All other switches have the
same meaning as of the original hpnpf (but haven't been fully tested with this version).