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Computer fax
If you have a document in your computer that you want to send by fax, you don't need to print it first and then scan it into a fax machine. With a fax modem and supporting software, you can send the document directly from your computer. Computer fax produces much better-looking images than a fax machine can. The software always puts every pixel in exactly the right place, and straight lines in the computer file are always perfectly straight on the copy. (Of course, you could also scan a paper original with a scanner hooked up to your computer and transmit that via fax, but, despite what the ads say, you'd be better off simply using an ordinary fax machine.)
Computers are clumsy for receiving facsimiles because you can't read messages until you print them (the resolution of computer screens is not high enough for fax images to be legible). The dots on most of the common dot-matrix printers for computers are too large to give a clear printout of a fax message. Laser printers have small enough dots, but they are designed to print at 300 DPI, not 200 DPI, so the image usually comes out a different size from the original, if you can print it at all. Many laser printers sold for IBM PCs, for instance, cannot print full-page graphics.
Computer fax modems can send images to ordinary fax machines and to other fax modems. They can also transmit computer files, but because there is no standard data format, a fax modem can exchange data only with an identical fax modem run by the same controlling software. An industry group has begun to define such a standard, which will enable any fax modem to exchange computer data with any other fax modem.
Given these drawbacks, you should not buy a fax modem until after you have a fax machine. Once you have both, you can use the fax modem for sending documents you have stored in your computer and use the fax machine for receiving all incoming facsimiles and for sending documents that exist only as paper originals.
From a technical -- or even practical -- point of view, it's ironic that fax machines are so popular. To begin with, fax technology is quite ordinary. It was originally developed for sending graphics; yet most facsimiles in North America consist only of text. Since most of this text is probably generated on computers in the first place, electronic mail would almost always be more effective than fax. Because fax sends pictures of characters, not the computer codes for those characters, you can send a page of text faster through a standard modem at 1,200 bits per second than you can fax the same page at 9,600 BPS.
And, unlike electronic mail, you can't edit text received via facsimile without having to retype it into your computer. (Some companies are promising to "read" facsimiles into computers with optical character recognition, but no one has yet done this convincingly.)
So why the appeal of fax? Because fax is fast, easy, and cheap -- and, probably most important, because people are better at getting the picture if they can see it on paper. Any technology that makes getting the picture easier as well as faster will be with us for a long time to come.
PHONES AND FAX
Should you give your machine a line of its own?
In the long run, the most expensive part of owning and operating a fax machine is the telephone line it is connected to. As long as you can afford it, the best way to run a fax machine is to connect it to its own phone line. The fax machine can then answer all calls automatically, incoming messages can arrive at any time, and no one has to be present to receive them.
If you really want to try saving money, you can use one phone line for both voice calls and fax, but you will have to put up with a few hassles. Sending fax messages on the same line you use for voice calls is no problem, as long as you remember not to pick up the telephone during a transmission. Receiving messages is another story. You cannot simply attach the fax machine to the line and let it answer the phone automatically because all callers will be greeted with the shrill beee of an answering modem. So to receive a fax, you must answer the phone yourself and then manually start the fax machine. This means that the fax machine must be next to your phone and that you or someone else must be present to turn it on -- two major inconveniences.
What about a switch that could route incoming calls either to a voice phone or to a fax machine? A standard international CNG (CalliNG) tone (beep-[pause]- beep-[pause]- beep) does exist that identifies nonvoice calls such as those from a fax machine or computer modem. An electronic switch can easily detect the CNG tone and route a call accordingly. But not every fax machine sends these tones; some send it only when dialing automatically, and some don't send it at all. Without a CNG tone, there is no completely automatic way to determine that a call is coming from a fax machine.
The solution is semiautomation. All calls need to be answered by voice, either in person or with an answering machine; if the incoming call is a fax message without a CNG tone, either the sender or the receiver can dial a code (typically by pressing the * or # button), which will signal a switch to route the call to a fax machine. If an answering machine is responding and fax senders know which buttons to press when the answering-machine message begins, no one need be present to receive fax messages. And for automated sending, the sender's fax machine can be programmed to dial, pause for your answering machine, and then dial the correct code (as long as the required pause is always the same length).
You can add a voice/fax switch externally to any fax machine. Vada Systems' $300 Faxswitch II can detect CNG tones and * or # signals. (This is the same as The Switch, model F/M/A, available from High-Tech Resources for $350.) These switches also prevent you from disturbing a fax transmission even if you accidentally pick up the phone. Some manufacturers are starting to build such switches into their machines. Sharp's model 300 and 420 fax machines feature switching, but they do not detect CNG tones; the new model 550 will.
RESOURCES
Where to get more information
If you want to find out more, here are the addresses of sources mentioned in this column:
Brother International Corp., 8 Corporate Place, Piscataway, NJ 08855; (201) 981-0300, (800) 284-4357
High-Tech Resources Inc., 4225 W. Glendale Ave., Suite 102, Phoenix, AZ 85051; (602) 931-0793, (800) 422-2832
Murata Business Systems Inc., 4801 Spring Valley Rd., Suite 108B, Dallas, TX 75244; (214) 392-1622, (800) 543-4636 or 4637
Sharp Electronics Corp., Sharp Plaza, Mahwah, NJ 07430; (201) 529-8200, (800) 526-0264
Vada Systems Inc., 9329 Douglas Drive, Riverside, CA 92503; (714) 687-2492, (800) 999-8232
What to Buy for Business, 350 Theodore Fremd Rd., Rye, NY 10580; (914) 921-0085, (800) 247-2185. $18 for fax issue, including updates.
