Enterprise-class system software designed to work in a network environment. Fax modems can be attached to a single machine on a network and clients can submit an outbound job from another computer on the network with related client software, which is lightweight and easy to port.

The fax server is designed to guard against unexpected issues related to the software, hardware or actual transmissions. The application was also built to give users confidence- it uses an intelligent scheduling for sending and optimizing retry attempts. Jobs are either completed successfully or the submitter is notified of what happened.

Facsimile can be any size (e.g. A4, B4), either 98 or 196 lpi, and transmitted/received as either 1D-encoded or 2D-encoded facsimile data (2D-encoded data is frequently more compact and hence takes a shorter time to communicate). Any modem that supports one of the standard interfaces for facsimile operation can be used; i.e. any Class 1, Class 2, or Class 2.0 modem.

Outgoing documents can be any format; the sendfax program uses a rule-based definition file similar to the System V /etc/magic file to deduce document types and to decide how to convert each document to a form suitable for transmission (either PostScript or TIFF/F). Automatic cover page generation is supported and users can easily tailor cover pages to their environment. A simple text-based phonebook database is supported by the sendfax program. Information is also provided on how to trivially setup an email to fax gateway service.
Incoming facsimile are stored in a receiving area as TIFF/F (read "TIFF Class F") files and may be automatically delivered by mail and/or printed. A fax server status program, faxstat, can be used to monitor the send and receive queues, as well as the state of facsimile servers.

The software is structured around a client-server architecture. Fax modems may reside on a single machine on a network and clients can submit outbound jobs from any machine that can communicate with the machine on which the modems reside. Client software is designed to be lightweight and easy to port; imaging can be offloaded to the server or done on the client. (Imaging is however, typically done on the server because it simplifies administration.)

Clients and server communicate over a protocol that is similar to ftp and you may also use ftp or telnet to communicate to the server directly. There are clients for different types of machines including UNIX, Windows®, and Mac. An access control mechanism is included to control which users on which machines may submit jobs.

Multiple modems on a single server machine are effectively scheduled for high throughput. Broadcast faxing is well-supported through optimal imaging of transmitted documents and the effective scheduling of modem resources. Support is provided for scheduling jobs during off-peak hours based on the destination phone numbers (e.g. long distance calls may be scheduled for off-peak phone rates). The access control mechanism can be used to restrict the class of phone numbers called so that, for example, calls to emergency services such as 911 can be rejected out of hand.

The server requires a PostScript to facsimile imaging utility for useful operation (otherwise, only pre-imaged facsimile may be transmitted.) A Display PostScript-based imager is provided for IRIX 4.x- and 5.x-based systems. For other systems, a Ghostscript-based version can be built from the GNU sources.