[Asterisk-Users] T.38 fax summary

[Rich Adamson]

Steve,

Excellent summary thus far!!! Will the summary stay on that url for a
lengthy period of time, or would it be possible to copy it to the wiki
when complete?

One item you might add to the T.38 discussion is a relatively short
paragraph that describes/relates the current analog fax environment to
T.38; by that I mean I don't have a clear picture in my mind as to
whether T.38 has any interconnecting relationship to analog machines.
Maybe some additional words that says something like... "T.38 capable
fax machines encapsulate the digital fax bits into tcp/udp packets and
sends those across a data network. To receive a T.38 data stream on
an analog fax machine, the equivalent of a modem or protocol converter
would be required to change the digital fax bits into an analog 
format compatible with the receiving analog fax machine's modem."

Since there is a very high interest in the asterisk community to
accomplish the T.37 approach (or stated slightly different, an interest
in receiving faxes in a pdf or tiff form instead of paper), could you
include a reference or two for products (open source or otherwise) that
accomplishes that task? (I'm assuming spandsp is one such approach, and
there are likely others. Something like... an analog fax modem when
combined with the linux app called "xxx" will provide the economical
conversion, but cannot be reliably used across voip.) The thought process
(at least for me) is that many commercial voip/asterisk implementations 
really need the emergency Red Phone support (eg, US 911 fall back), and 
in many cases that analog pstn line could be the same as an incoming 
fax line. (Rather small price to pay to cover both legal liablilities
and fax images in the current voip environment.)

Back in the olden days, I recall several modem vendors bundling PC fax
software with their products. All of those old Win v3.1 apps created
a fax file (eg, pdf or otherwise) that could be distributed via email.
What are the equivalent low-overhead approaches (sort of T.37) today?
I'd be very happy if I could simply connect an old analog 28.8 modem
to the asterisk serial port, and drop a low-overhead app onto the 
system to address the fax stuff for today. Something very basic.

Rich

------------------------
> Hi,
> 
> Questions keep comming up about this, so I started writing something at 
> http://www.soft-switch.org/foip.html . I think I covered the FAX over 
> VoIP issues fairly completely. T.37 is pretty simple to explain. There 
> is rather more to say about T.38, but at least this is a start. If 
> anyone wants to suggest corrections or additions, just blurt them out.
> 
> Regards,
> Steve
> 
> 
> Rich Adamson wrote:
> 
> >Steve Underwood,
> >
> >Would you mind summarizing where/how T.38 functions, and maybe how it
> >compares to the analog fax environment for the asterisk-users arhives?
> >
> >Seems to be some misunderstanding, and a lot of interest in handling
> >faxes in various forms via asterisk. If some these approaches were 
> >summarized in one posting, a lot of us could reference it to remind us
> >of limitations, current state, etc. A few short paragraphs would be 
> >helpful.
> >
> >Rich
> >  
> >
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