[Asterisk-Users] OT: fax obsoleted? Was: Re: Fax via email

[Lee Howard]

On 2004.06.11 20:47 Steve Underwood wrote:

> The last info I got from a large FAX server is about a year old. It 
> seems after several years of nothing much changing, FAX has suddenly 
> taken a step up - kind of sad it should improve now it is obsolete :-)

Fax was only partially obsoleted.  Users, developers, and manufacturers 
alike all "foresaw" the end of fax with the coming of the internet 
age.  They were only partially right.

In the old days, before the internet became ubiquitous, fax was used 
quite extensively for document retrieval.  So if you had 
document-information that you wanted to make available to others then 
it was popular to put them up on a "fax-on-demand" service, and the 
inquirer would either receive the documents to their fax machine via 
polling, or by "fax back".  This usage of fax has almost completely 
been obsoleted by the internet browser and by PDF.  In the old days 
everyone who was anyone had a fax-on-demand service.  These days that 
has been obsoleted by the website.  So yes, receiver-initiated document 
exchange has largely been replaced by websites.

There were also plenty of examples where people would use fax as a 
means for small, somewhat unimportant, message communication - the 
equivalent of today's e-mail.  Obviously e-mail has obsoleted this.

However, fax is still very much alive and healthy in the area of imaged 
document exchange where the website or e-mail use would not be 
appropriate - i.e., where the sender wants to initiate the document 
exchange and the document is in a more-than-text form or image of some 
kind (applications, completed applications, handwriting, etc.).  
Furthermore, I don't see this usage of fax going away any time soon.  
Indeed, technology seems to be providing better and better ways for 
this to continue, and I see no end to this sender-initiated use of fax.

It's worth pointing out that e-mail works off of a different premise 
than fax, and therefore cannot ever fully obsolete fax as it is.  
Unlike a website or fax, e-mail does not provide a mechanism for both 
the sender and the receiver to negotiate the communication and 
presentation of the document.  E-mail permits the sender to send 
arbitrary filetypes with arbitrary formatting which the receiver may or 
may not be able to utilize easily.  With a website the receiver should 
be aware of what they are clicking on, and with fax the receiver 
"capabilities" are communicated at the outset to the sender, and the 
sender must select tranmission parameters from those capabilites.  
Thus, with fax the sender can have a reasonably good degree of 
confidence that when the receiver sends the confirmation signal (MCF) 
that the receiver can view the document and that it appears to the 
receiver nearly exactly the same way as it appears to the sender.  Not 
only can you not do this with e-mail, but furthermore with e-mail you 
only know that your outbound mail relay has accepted the mail or not.  
You do not have any reassurance that that the intended recipient 
actually did receive the message.  And with the large amount of spam 
out there (very large in comparison to the quantity of junk faxes), 
spam filters, e-mail viruses, and such, e-mail really isn't a very good 
means to transmit these kinds of things.

The fact that faxing has traditionally been done over POTS/PSTN lines 
is largely irrelevant, I think.  Technology such as VoIP/FoIP is 
providing a means for fax to utilize the internet, and I only suspect 
to see an increase in the demand for fax-ready or fax-aware VoIP 
equipment or software.  So fax modems may become obsoleted with the 
growth of the internet (it's going to take a long while for broadband 
to get to everyone with a fax application, though), but fax itself will 
still be there, running on things such as t38modem and your 
spandsp/rxfax/txfax.  It's not going away.

> The 33.6k feature has certainly spread considerably in the last year 
> or two.

V.34-Fax is a smart thing for fax.  Not only does it make the total 
communication take less time in most cases, but the fact that V.34 is 
used continuously throughout the session *without dropping and raising 
the carriers* makes it very stable.  Without V.34-Fax you have to drop 
and raise the V.17/V.29/V.27 primary carrier and the V.21 control 
carrier frequently, and every time that happens there is a risk of 
losing synchronicity due to noise or timing problems.

Fax machine manufacturers that want to have happy customers first make 
sure their products supports ECM (requires 64K RAM per line, so there 
is an actual hardware difference - not just firmware).  Users won't 
know what this means, except that they'll get perfect faxes nearly 
every time.  They'll eventually toss those cheap non-ECM fax machines 
when they have communication problems that are resolved when they go 
and buy a nicer ECM-supporting fax machine.  They won't realize that it 
was ECM, they'll just know that the cheap fax machine didn't do as good 
a job as the not-as-cheap one.  Likewise manufacturers that want happy 
customers will implement V.34-Fax not just for faster faxing, but 
because it provides a more stable fax medium.

So, I guess what I'm saying, is that inevitably there is going to be an 
FoIP solution that supports both ECM and V.34-Fax.  If you want your 
product to be the standard-bearer, well, thinking that fax is obsolete 
will not be helpful.  :-)  If you really are looking for the path of 
least effort, I would recommend that you forget most of the fax 
protocol - like t38modem, leaving the faxing up to applications like 
HylaFAX, efax, or whatever - and merely work at an AT-command interface 
(Class 1/1.0 should be sufficient) application for spandsp, say 
"spandspmodem".  That should be significantly more simple.

Lee.