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after several years of nothing much changing, FAX has suddenly taken a step up - kind of sad it should improve now it is obsolete :-)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 So yes, receiver-initiated document exchange has largely been replaced by websites.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.
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