High-Volume Faxing on Mac

While I would like to explain how to handle high-volume faxing completely on a Macintosh server, this page is actually an explanation of why that cannot be done reliably.

Lee Howard’s excellent HylaFAX+ software builds and runs perfectly on Macintosh OS X. If you're familiar with UNIX command-line software builds, you just go through the very typical ./configure + make + make install process for 2 dependencies (libtiff and Ghostscript), then HylaFAX itself. But that's mostly irrelevant, because you will not get a suitable modem working reliably!

Most stand-alone fax machines, even cheap ones, support “Super G3” 33.6kb/s transmission speeds—and in actual use I find that they very often achive actual transmission speeds of 28.8kb/s or more. Consumer-grade fax modems usually advertise 14.4kb/s faxing which would be a 1/2 speed disadvantage already. But the advertising is deceptive; what they actually provide is 14.4kb/s for receiving faxes but only 9.6kbp/s for sending; so that is a 1/3 speed disadvantage for sending. In addition, Super G3 includes more advanced compression and error correction options, so in actual use the difference in per-page transmission time is even greater than the 2x - 3x difference in the transmission speeds.

If you are dealing with high-volume faxing you simply cannot afford to use any modem that does not support the higher transmission speeds. It’s more than just an annoyance of faxes taking longer to send & receive, or even charges for long-distance calls; it’ a matter of how many lines you would require to support your fax volume. Tripling the number of phone lines you pay for in order to compensate for using crappy modems is not realistic.

Faxing is a shrinking business and there are fewer and fewer products available. The only currently available external fax modems which support 33.6kbp/s speeds are from MultiTech. The USB MultiTech modems lock up frequently under heavy use, while the serial MultiTech modems cannot be used because there is no USB -> serial adapter available that has a reliable driver for OS X. And there are no suitable internal modems, even for a Mac Pro, because of the lack of driver support for OS X.

After about 18 months of trying every combination of modem, adapter, and driver version, we moved faxing off the Mac onto a generic Dell box running CentOS and with a MainPine fax board. This combination has a problem requiring attention about once every 6 months. Not perfect—but vastly better than multiple times every week, and even multiple times per day, like what we had with external modems on a Mac.

The good news is that HylaFAX has a client/server architecture, so that even with it running on a Linux box, you can build it on the Mac, and send/receive faxes much the same as you would if the Linux box were not involved. For many of the commands you just add an argument with the IP address of the Linux box. Of course there's more configuration; you have to configure things so that you can move files between the boxes as needed, the HylaFAX log files that you might want to parse will be on the Linux machine, and so on. So high-volume faxing can be integrated with Mac servers in a way that is fairly clean, and very reliable.