asterisk users - May 2005 - Asterisk - fax - spandsp <--older threadlet from Jean-Yves about fax corruption, *not* timing

> Actually.. I seem to have jumped to improper conclusion..

One thing you will find abour spandsp is that some fax machines will just
plain have a problem sending to spandsp, period. Mr. Underwood has localized
it to cetain HP fax machines and I can confirm that HP all-in-one SOHO
machines exhibit this problem, but I have also noted it with Canons and
Panasonics. In my context, I have several hundred fax machines (~400) that
can potentially send to me, and a certain percentage exhibit this problem.
Of these fax machines, I have narrowed down a list of 12 that constantly
crap out when using spandsp. My workaround, while not very elegant, solves
the problem for me: When a call comes in matching callerID X, forward the
call to a "real" fax machine:
 
exten => 5555,1,Gotoif($["${CAALLERIDNUM}" = "5555551212"
]?,2:3)
exten => 5555,2,Dial(ZAP/g0/5552222,60)
-keep going down the list until the list is exhausted, then kick in RxFAX-
 
In the end, for me, it was a tradeoff between the flexibility of spandsp vs
these niggly little problems, and if you do the math, in my case it's only
3% of fax machines exhibit the corruption problem, so it was worth it to do
this workaround and train the office gopher to check the "real" fax
machine
every couple of days. 
 
FWIW, I did a back-of-napkin calculation using spandsp vs our old method of
having a bank of fax machines and came up with an astonishing 40,000 sheets
of paper saved annually, with a cost of over $10,000 cdn saved annually
(this included labor costs to distribute the paper fax + our "click
rate" on
our fax / copiers) and we get the added bonus of taking the generated PDF
and attaching it to our in house CRM; if you can believe it, we used to take
the fax (on paper) and scan it into our CRM as a PDF, and spandsp + tiff2ps
+ mine-construct took care of this step for us. So for me, it was totally
worth it to go through teething problems with spandsp and I would not go
back for a second. 
 
 

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