* Illustration: Siggi Eggertsson * Who hasn't put a perfectly good fax machine on the curb? In those hasty moments of purging, you think, "I don't need this dinosaur. Who faxes anymore?" Hope it wasn't a really nice one you junked, because someday you'll wish you had it back. The facsimile isn't going anywhere.

Patented in 1843 and mainstreamed sometime between the 8-track and the CD, the technology is like a B-movie zombie that keeps lurching forward—clumsily, relentlessly—long after it should be in the ground.

Fax machines are everywhere: doctors' offices, delicatessens, brokerage firms, even souvenir shops in the developing world (for verifying tourists' credit cards).

The device's particular skill is well known: It makes a replica of a document appear in another location in seconds. When machines dropped in price in the late '80s, their closest competitor was hand delivery—not a tenable solution for people trading paper over long distances. Soon, courts gave the tech a crucial blessing by certifying that a facsimile of a signature was legally valid. By 1990, faxes were the way to take care of everything, from securing a mortgage to ordering a ham on rye.

The fax's real rival today is the PDF—essentially the same idea, but with far more complex hardware. But even with the prevalence of email, the number of people who can send and receive faxes is still increasing. According to market research firm Gartner, sales of stand-alone fax machines may have plummeted, but sales of multifunction printers—which also copy, scan, and, yes, fax—increased 340 percent from 2001 to 2007.

Although the fax function of millions of those machines is all but ignored, it can be a lifesaver in an emergency. Say you break down on some lonesome road in Pennsyltucky and call your insurance company for roadside assistance. Progressive will probably fax an authorization to the tow company—not drop Joe the Wrecker an IM. Why not just email him? They might not have his address, and he might not be able—or inclined—to open a PDF. But he almost certainly has a fax number, it's probably listed, and his machine can receive a transmission from any source—a brand-new multitasking office bot or a 25-year-old thermal-paper fountain. This universal utility is the technology's competitive edge. Faxing is easy. "It's a self-contained appliance, and that's a lesson to us as information technologists," says Ken Anderson of market research firm Burton Group. In other words, it's still the most elegant solution.

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