HylaFAX supports a wide variety of modems and is designed to support any Class 1, Class 2, or Class 2.0 modem without modification to the source code. If you have a modem that provides only a Class 1 interface then HylaFAX is likely to be the only freely available software package that will work with your modem.
HylaFAX supports multiple modems and heavy traffic load. If you expect to send or receive more than 1 or 2 facsimile a day, then HylaFAX is likely to be the best package for you to use.
HylaFAX is expressly designed to be highly configurable without modification or access to the source code. The software comes with extensive documentation to assist in understanding how the software functions and how to configure it.
HylaFAX is freely available. There is no GNU copyleft policy. There are no requests for remuneration, constraints on use, or constraints on incorporation into products (compare this with other ``freely available fax packages''). The software copyright only restricts the use of the author's name and/or Silicon Graphics' name in any advertising; consult the copyright text for details. There are binary distribution packages or other formats for several Unixes.