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PDF over SMTP to Replace Traditional Fax

August 22, 2011

I really enjoyed being a part of the revolution that helped move traditional voice services from the PSTN to IP. Merely moving voice from a switched circuit network to a packet-switched network was not the reason for my interest in the field of multimedia communications, though. I was interested (and remain interested) because IP networks open up the door to a world of rich communication capabilities. With IP, there are so many more modes of communication that are possible. Concepts like the Advanced Multimedia System are really cool, where one can utilize a device (like a mobile phone) and communicate with various other devices on the network to realize a powerful and rich communication experience. One can utilize an electronic whiteboard on one device, while having a video stream on another device, and transfer a file in the background on a third device.

All the while, though, there is one ancient piece of technology that simply will not go away. As much as I wish it would, people still insist on using it. That technology is the PSTN facsimile machine.

I was also one of the people that helped to define the standard for transmission of Fax over IP (FoIP). To be fair, I was not the person who designed the first version of the protocol (known as Recommendation ITU-T T.38). Even so, I played a significant role in helping to ensure its place in the IP world. I did not do that work because I liked T.38, though. On the contrary, I have always been of the mind that T.38 did little more than perpetuate the PSTN and a better solution should have been delivered to the market. T.38 exhibits all kinds of problems, especially when there are multiple PSTN gateway hops in the call path. The protocol is very sensitive to end-to-end round-trip delay and, as a half-duplex technology, there are often collisions on the PSTN circuits that cause calls to fail. If that were not enough, some service providers do not provide proper treatment of the modulated signals, sometimes even running them through voice codecs! If you have experienced problems sending faxes, it might very well be due to the fact that the faxes are going over an IP network.

Still, I cannot fault the original designers. At the time the specification was first written, device capabilities were limited and the designers had to make certain choices. Moreover, many of the current-day problems with T.38 will disappear as fewer and fewer PSTN gateway hops are inserted in the end-to-end media path. I look forward to that day, but at the same time I have to ask, “Why do we live with fax at all?”

The answer to that question is simple. It is the reason I was asked to work on T.38, related session signaling protocol support, security enhancements, and so forth. Fax is an important part of day-to-day business for many businesses and government agencies. Many companies around the world rely heavily on their fax machines to get business done.

Even so, there is a better solution on the market and it has been there for years. It’s called “PDF over SMTP”. It is a very simple technology for end users to use, too. All one has to do is send an email and attach a PDF document. There are even multi-purpose devices sold in office supply stores now that will scan documents and email them as PDF documents to people anywhere in the world. It is just as easy to use as the legacy fax machines, provides the same or better security, reduces wasted paper, reduces cost, produces a higher-quality black and white or color document, and completely side-steps all of the transmissions problems that exist with legacy fax machines. Further, it is a completely standard solution to the document transmission problem!

Seriously, we should all switch over to using email to send documents and stop using the old fax machines. I am absolutely amazed that the world has not already moved away from that old technology, but my guess is that many people are simply unaware that there are many models of printers and scanners already on the market that have PDF over SMTP capability. Here is one such high-end model and a low-end model. Perhaps the problem is simply that nobody calls it PDF over SMTP. In fact, none of the vendors have a name for this capability. So, I plea to device manufacturers: call it PDF over STMP so customers know they can get away from the old fax machines they are currently forced to use.

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