What’s a Fax, Anyway?

12 Apr What’s a Fax, Anyway?

Quick! Define the term “fax”. Well, if you really try, you may find that defining fax is a little like defining “marketing”, a word everyone believes he knows how to define. Often, the more common the word the more difficulty one has in defining it. But the term fax (facsimile), as it is important in the world of telecommunications, is surrounded by patents, and is, therefore, the subject of intense legal scrutiny. So, the legal eagles arm wrestle over the definition.

So, what is it? Of course, “fax” (or facsimile) is a noun: you refer to the received image as “a fax” and refer to the terminal as “a fax.” It’s an adjective: “fax machine”. It’s a verb: “I faxed the document to you.” But the courts seem to be concerned with the process. What, really, constitutes the process or method of “faxing”?

You could resort to the dictionary and look up “facsimile” and talk about it being an exact copy of the subject document. You would also read about facsimile terminals that are used to send images over the telephone network. So let’s “drill down” as they say (or used to), and see what we find.

A few years ago I was an expert witness in pre-trial proceedings in a case that hinged on whether a fax terminal was a computer, so we had to be concerned with the legal definition of “computer” and “fax terminal”. I wrote:

With the exception of IP, the Internet Protocol, the Group 3 (G3) facsimile (fax) standard is the most popular computer-to-computer protocol ever. Although fax, the ability to transmit an image electronically over distance, has been in existence for over 100 years, G3 fax, the standard used hundreds of millions of times every day, was first published as an international standard in 1980. In this report we will use facsimile, fax, and G3 fax to mean an electronic device that implements the Group 3 fax standards specified and referenced in the ITU (International Telecommunications Union) T.4, or the Group 4 standard specified in the T.6 recommendation.

Not bad, if I do say so myself, since this is, essentially, what the US Central California District Court came up with a little later. That case hinged on whether a fax-image file e-mailed to an intended recipient by a store-and-forward computer system was a fax. There was a lot of legal verbiage around the judge’s so-called Markman ruling, but the key finding was that an e-mail with an attachment was not a fax. The court wrote:

For a machine to be a “fax” machine that sends “fax” messages, it must use a certain protocol-what the parties often refer to as a “digital dialogue”-to communicate. Otherwise, nothing distinguishes these machines from any other machine used for communication.

The court continued:

Given the foregoing, the Court finds that it is clear from the language of the claims that “facsimile protocol” means the standardized procedure that governs the transmitting and receiving of facsimile messages, excluding other protocols whereby the substance of a facsimile message is converted into a different format and then retransmitted using some other protocol.

So, the thing that makes a fax a fax is the protocol used to send the image from A to B. It’s interesting to compare the careful language of the court ruling with Wikipedia:

A fax (short for facsimile) is a document sent over a telephone line.

You might be wondering what the ITU recommendations say. T.4 is the top-level recommendation for G3 fax. It states:

This Recommendation defines the characteristics of Group 3 facsimile terminals, which enable documents to be transmitted on the general switched telephone network, international leased circuits, and the Integrated Services Digital Network (ISDN). These terminals enable black and white documents to be transmitted and also optionally color documents…The procedures (the “digital dialogue” of the ruling) to enable Group 3 facsimile terminals to communicate using the above capabilities are defined in ITU-T Recommendation T.30.

So, to summarize: a fax is an encoded image (as specified by T.4 and T.6) that is transmitted over the switched telephone network from one communications endpoint to another using the procedures defined in ITU recommendation T.30.

I did not find any explicit references that would help answer the natural questions regarding whether the circuit can include non-PSTN segments (e.g. IP) with the result still being a fax. I suspect that any court cases that exist or will exist will conclude that the critical item is that the endpoints use T.30.

If you know, please respond to this posting.