On Oct 24, 2008, at 12:49 PM, Wilton Helm wrote:
I've been following this thread and trying to sort out what is
wanted, what is available, and why. Comments to the following would
be appreciated and might be useful to others.
1. Why would anyone originate a FAX via VoIP? If it has to go
through a bunch of translation steps at both ends, it would seem
better to simply scan the document (assuming it isn't in electronic
form to begin with) and attach it to an E-Mail.
Because I don't want to pay to have one single POTS line running into
my office when it's sole purpose is for fax. I would much rather get
that fax into my asterisk in some intelligent manner and have one less
company to pay.
2. Why would anyone terminate a FAX call coming through Asterisk in
a FAX machine? Isn't there a way to capture it electronically? If
so, it seems that putting the electronic documents in a queue where
people can open them, save them, and if they wish, print them would
be much more useful (and planet friendly, since a lot aren't worth
putting on paper).
I fully intend to do this, once the faxes gets into my * I email it
off to someone.
IMHO, there are only three realistic needs:
A. Electronic end to end document transfer which is best done with
E-Mail and not telephony.
As others have already mentioned, faxing is still around due to user
ease and legal reasons. : (
B. Receipt of FAX from outside (old school) sources, which is best
done electronically.
I agree.
C. Generation of FAX to outside (old school) destination, which
could be done either electronically or in the traditional manner.
My user base is fairly intelligent, so I will most likely be doing
this, but we still have a need to be able to fax someone outside our
organization, for that reason we still must have a reliable way to get
faxes to plain old fax machines. I hope to do this with a solution
that converts an email into a fax then sends it off into the normal
analog tubes.
If end to end FAX is desired, is there any reason why Asterisk
should treat it any differently than any other call? The FAX
machines on each end generate and decode the information, VoIP is
simply an audio channel through which is passes.
Voip is a bit too loose of a term for describing this process when it
comes to faxes. For the audio signals your speaking of to be
recognized the standard analog audio range must come through clearly,
lossy voice codecs hack that spectrum up to save bandwidth. While this
is ok for humans, it kills the fax signal. This is what t.37 and t.38
try to fix. You can go read up on them elsewhere, but basically they
allow faxes to be sent in a packetized manner that can coexist well on
a data network. The trouble obviously being that normal (most anyways,
some support t.38... as Steve`Underwood has been saying, albeit
somewhat buggily) fax machines can't understand this. This is why t.38
must be decoded at some point before getting sent to a plain fax
machine.
And that is why I am looking for a way to decode/encode my faxes with
t.38, to avoid having to pay a phone company for one analog line that
would get used at most a few times a week.
I don't know what T38 defines or implies, but if it is anything
other than how to electronically decode a voice call that happens to
contain FAX information (rather than passing it on to a real FAX
machine) then I'm not sure what use it is. It would seem to me that
the OP needs a way to electronically capture calls that turn out to
be FAXes.
Right, see above.
Wilton
Anyways, I hope that helped you understand my desire to set things up
how I am trying to. I'm sure a lot of people are trying to do this /
have tried / have done it. Hopefully this thread will help those
having trouble figuring out how this is done when they start
googling. : )
Brendan Martens
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