The first fax machines looked much like current models only bigger—and usually smellier. Each had a telephone handset and a touch-tone keypad for dialing a distant machine. Each had a slot to slide in documents and another where received pages slid out, often a bit damp from the primitive chemical-based printing technology. Today, the fax machine combines several other office functions—a fax modem with a scanner, printer, and telephone set—that would tempt you to tie in your computer, but the standalone fax machine puts all its goodies out of the reach of your computer and its applications.
Today, standalone fax machines survive because, compared to computers, they are easier to use—they have no need for the hassle of clicking through windows or even booting up a computer to simply dial the telephone. Moreover, most fax machines are designed as—and perceived as by office workers—ordinary business machines, nothing so exotic or esoteric as a computer. They are seen more as a telephone with a paper slot than a brain-draining thinking machine. Even unskilled office workers are unfazed by a standalone fax machine.
A document whisking its way across the country is nothing more than digital data. Once that simple fact registered on computer engineers, they figured out ways of linking that data with the day's best data manipulator—the personal computer. The solution was the fax modem. Briefly, a small industry flourished making modems that could give your computer fax capabilities. Then the technology went mainstream, and the fax modem became a de rigueur part of every computer.
Fax machine–makers got another idea that they could give you the best of both worlds with standalone fax machines that accepted data such as telephone lists through a cable connection with your computer. Modern technology has done those simple connections one better—maybe four better. Multifunction printers often start with an ordinary fax machine but give your computer direct access to individual fax functions. The one multifunction printer can also serve as both a printer and a scanner for your computer—at least if you don't demand graphic arts-quality scanning. Or you can slide a sheet of paper in, press a button, and have a digital copier. At a more mundane level, you can pick up the receiver and use the multifunction printer as an ordinary telephone. One manufacturer has even added an answering machine to its fax printers.
In the computer realm, the term fax modem means an expansion board that slides into a vacant slot inside your computer to give it the capability of sending and receiving fax transmissions. Although at one time it took a specialized product to handle faxes, even the least expensive of modern modems include fax capabilities.
The fax modem converts rasterized documents and page scans into a form compatible with the international telephone system. Nearly every high-speed modem sold today has built-in fax capabilities. This bonus results from the huge demand for fax in the business world, coupled with the trivial cost of adding fax capabilities to chips used to build modern modems. Everything that's necessary for fax comes built in to the same chipsets that make normal high-speed modem communications possible.
The fax sections of multifunction printers are little more than ordinary standalone fax machines. Nearly all commercial products use the same chipsets as fax modems. They differ chiefly in the capability of their standalone functions: how many numbers they remember and organize.
The printer sections of multifunction machines vary widely, nearly as widely as ordinary printer technology. The least expensive multifunction machines use inkjet printers. Although at one time the bargain-basement machines got away with including only monochrome printing, nearly all inkjet-based multifunction printers now have color capabilities. That doesn't mean the machines can send and receive color images. The color serves only the computer printer function, so you have the full spectrum available to you when want you want to print, for example, a page from the Web.
Nothing precludes a multifunction printer from using other technologies, and a few more expensive machines do use laser engines. You get all the advantages of a laser printer—fast, sharp images on plain paper—along with the ability to send fax directly from the printer or through your computer. As with other general-purpose laser printers, you're restricted to monochrome printing, both for fax and general computer output. (No manufacturer has adapted color laser technology to fax printing.) Fax standards limit the resolution of documents received by fax to 200 dots per inch. Scans and copies are limited by the resolution of the scanner section. Output from your computer, however, prints at the hardware resolution of the print engine.
Most multifunction printers use drum scanner technology. It is less expensive to move paper than it is to move an internal scanner. Drum technology also permits more compact machines and makes adding document feeders for multipage faxes much easier. A few multifunction printers use flatbed scanners. Although these are not as useful for faxing (document feeders for them are expensive add-ons), they add versatility to the scanning function. As with other flatbeds, they allow the use of small and odd-shaped documents as well as three-dimensional objects (such as books) that would be off limits to a drum scanner.
The scanners in multifunction printers are optimized for fax use and do not pretend to compete with dedicated scanners for producing high-quality graphics. They often have limited resolution (some as low as 200 dpi), limited dynamic range, and sometimes no color capabilities at all. Fax doesn't need color. The output is, however, sufficient for document processing and works well with OCR software on your computer.
To make copies, the multifunction printer manufacturers simply link the fax scanner to the printer. The connection is indirect, detouring through the microprocessor and memory, a scenic route that adds versatility. You can make multiple copies (up to 99 on each machine) and, with most machines, alter the size of the image. On the downside, quality is limited by scanner resolution (no chance of counterfeiting $20 bills with a multifunction machine), and speed is constrained by processing and the printer engine. Some machines take nearly a minute to copy a single page, although speeds are increasing.