4.5.4 MFP faxing with T.37

Many multifunction printers allow for OSCAR to fax directly through them

Preface

T.37 is an ITU standard which deals with sending fax messages using email. It is also referred to as "iFax", "Internet Fax", or "Store-forward-fax".

A T.37-compliant fax machine will receive emails which have the document attached (using the MIME format) as a TIFF-F image.

The two step process to deliver T.37 faxes from OSCAR involves

converting the OSCAR provided pdf to TIFF with ghostscript
MIME encoding the tiff file and sending it to the T.37 compliant MFP

Document Version History

v1.0 – initial public release to oscarmanual.org – Dec 29, 2015
v1.1 – added debugging hints – Dec 30, 2015

development of this approach has greatly benefited from the work of Darius on whose work this document is based

Contents Preface Document Version History Prerequisites Installing Server Packages Now a Cron job Debugging

Prerequisites

It is assumed that

You have installed Oscar and configured it for faxing
You have a T.37 compliant multifunction printer (MFP)
You have a basic level of Linux knowledge
You can open a Linux terminal
You can cut and paste EXACTLY the following instructions

NOTE: Firefox will copy with Control+C while a Linux terminal requires Shift+Control+V for past

Installing Server Packages

Sendemail is a command-line outgoing e-mail SMTP client written in PERL. It is used for sending e-mails from the command line.

Ghostscript is a pdf generating and manipulating program. In this case we are using it to form TIFF-F files.

Install Sendemail and Ghostscript by typing or pasting the following into the command line.

sudo apt-get install sendemail ghostscript

Now a cron job

With the deb installation OSCAR uses iText for prescriptions and wkhtmltopdf for eForms to generate pdf's for faxing. These files are dropped into /tmp/tomcat6-tmp with the image to be filed as the pdf and as matching txt files with the fax number. These files can be parsed by a script that runs regularly, and assembled into an email that is sent to the MFP attached to your local network.

We don't recommend any MFP in particular, this protocol has been shown to work in principle with some Brother multifunction printers although most manufacturers provide this support for their MFP's. Look for documentation specifying T.37 protocol support prior to purchase.

Save the following as gateway.cron. (note that you should check the path for the tmp file, it can be /tmp/tomcat6-tomcat6-tmp/)

#!/bin/bash
#
# T.37 Fax cron
# Picks up the files dropped by OSCAR for faxing
# converts the pdf to a TIFF and sends to a MFP via T.37
# OSCAR and this file are on 192.168.0.1 and the MFP is on 192.168.0.2 listening on port 25
# Make sure you adjust the paths and URLs appropriately
#
if test -n "$(find /tmp/tomcat6-tomcat6-tmp -maxdepth 1 -name '*.txt' -print -quit)"; then 
	for f in `ls /tmp/tomcat6-tmp/*.txt`; do
		p = $f | sed s"/txt/pdf/"
		t = $f | sed s"/txt/tiff/"
		gs -q -sDEVICE=tiffg3 -r204x98 -dBATCH -dPDFFitPage -dNOPAUSE -sOutputFile=$t $p
		sendemail -f sender@192.168.0.1 -t FAX=`sed s"/ *//g" $f|tr -d "\n"`@192.168.0.2 -m fax -a $t -s 192.168.0.2:25
		rm $f; 
		rm $t; 
		rm $p;
	done  
fi

Save the file with execution privileges.

You may then run the gateway.cron as a cron job with a user that can read and delete the files in the temp folder (by example the tomcat6 user)

thanks to Darius who developed this technique and Kevin Boyle who suggested it

Debugging

The above cron job has not been tested in production beyond a proof in concept.

Configuring the MFP is beyond the scope of the tutorial and is device specific. The T.37 functionality may be turned off by default, and you may need to set and specify the MPF's IP and port for SMTP.

You do not need to debug on the OSCAR server. The software that OSCAR often uses to generate pdf's (wkhtmltopdf) and those software described for the OSCAR server cron job (ghostscript, sendemail) are all available as programs that run on Windows(TM) and other operating systems.

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