Logo IMG
HOME > PAST ISSUE > Article Detail


Fax and Context

Henry Petroski

Further Developments in Fax Machines

Both mechanical and electrical engineers, working individually and in groups on various aspects of the machine, played important roles in the development of the fax from a clumsy and slow analog device that used smelly paper to the compact, fast and user-friendly machines that became as familiar as copier machines and telephones. In the early 1990s, for example, a group of Hitachi researchers and engineers wrote a paper on "compacting technologies for small size personal facsimile," which appeared in the Transactions on Consumer Electronics of the Institute of Electrical and Electronics Engineers. The six authors, led by a senior investigator whose name, Toyota Honda, suggested more an automotive than a communications engineer, came from five different divisions of the company. The paper reported on two developments that were found necessary to produce a "small size personal machine," one involving rollers, which is clearly a mechanical engineering problem, and the other involving a computer chip, clearly a electrical engineering problem. Since home faxes are also expected to double as copiers, the quality of the image produced was very important.

Not surprisingly, the research paper of the Hitachi engineers does not reveal many of the details of how they ultimately solved their problems, but this is to be expected in an industry in which success depends so much on having a competitive product advantage. Industrial secrets cannot last long or be effective indefinitely, however. As soon as the new Hitachi compact fax machine was released, competing companies could buy it as easily as consumers could. Engineers learn a lot about different ways of solving problems by taking things apart, an activity that many engineering students engaged in as children and many engineers continue to do throughout their lives. Learning to make a new machine by taking apart something of the competition's is known as reverse engineering, and by such a process it would have been immediately obvious that a big advance in the new Hitachi fax was its reduced number of motors and rollers. Understanding how the quality problem was solved would take a little more work, but in time engineers working for competitors could figure it out or at least understand the problem well enough to come up with an alternative and perhaps better solution, since patented devices, of course, cannot just be copied. It is in such ways that competitive consumer products come to evolve into similar yet different forms. Because manufacturing companies know that their products are never safe from reverse-engineering scrutiny, and that they cannot maintain their competitive advantage for very long, research, development and engineering groups are an essential component of an active industry.

As the size and price of fax machines continued to be reduced, while reliability and quality of image seemed to be constantly improving, the question of speed of transmission remained an issue, at least with some manufacturers and users. Increasingly sophisticated encoding schemes required less data to be transmitted and hence decreased the time it took to scan and send a page. But the limiting factor was the 9,600 bits per second that could be carried over the public telephone networks. In fact, fax technology had become so sophisticated that when a machine detected that it had gotten a noisy telephone connection, successively lower modem rates of 7,200, 4,800 and 2,400 bits per second were automatically employed until one of these fallback speeds proved reliable.

The question of transmission speed led to the introduction of a new standard in 1984, and faxes that fall within it are known as Group 4. In this category, fax machines are designed to communicate over the integrated-services digital network known as ISDN. However, since ISDN itself did not become widely available as soon as originally expected, largely because local telephone networks and switching exchanges were not yet upgraded to ISDN capability, a decade later there were still relatively few Group 4 faxes operating. As with virtually all new technologies or technological advances, the situation attracted the attention of skeptics and nay-sayers and encouraged them to quip that ISDN stood for "It Still Does Nothing" and "I Still Don't Need." Whether the letters might ever stand for "I Sure Do Now" depends on what other new technologies might be developed before the ISDN network becomes widespread and before the costs of Group 4 fax machines drop enough to make them fully competitive. By the mid-1990s, there were promising developments that ISDN would indeed become the "Interface Subscribers Definitely Need."

What new alternative technologies might be developed is not merely a technical question, as the case study of the fax itself makes clear. Even the most technically advanced problems have nontechnical components that affect their solution. Cultural, social, economic and political developments can be limiting factors as much as are the physical laws that govern electronic circuits and mechanical movements. Henry Petroski is A. S. Vesic Professor of Civil Engineering and Professor of History at Duke University, where he also chairs the Department of Civil and Environmental Engineering. This column is adapted from his new book, Invention by Design: How Engineers Get from Thought to Thing, just published by Harvard University Press. Address: Box 90287, Durham, NC 27708–0287.

» Post Comment



Subscribe to American Scientist