A fax server
is a set of software
running on a server computer
which is equipped with one or more fax
(or dedicated fax boards) attached to telephone lines (or, more recently, software modem emulators which use T.38
("Fax over IP") technology to transmit the signal over an IP network). Its function is to accept documents from users, convert them into faxes, and transmit them, as well as to receive fax calls and either store the incoming documents or pass them on to users. Users may communicate with the server in several ways, through either a local network or the Internet
. In a big organization with heavy fax traffic, the computer hosting the fax server may be dedicated to that function, in which case the computer itself may also be known as a fax server.
For outgoing faxes, several methods are available to the user:
- An e-mail message (with optional attachments) can be sent to a special e-mail address; the fax server monitoring that address converts all such messages into fax format and transmits them.
- The user can tell his computer to "print" a document using a "virtual printer" which, instead of producing a paper printout, sends the document to the fax server, which then transmits it.
- A web interface can be used, allowing files to be uploaded, and transmitted to the fax server for faxing.
- Special client software may be used.
For incoming faxes, several user interfaces may be available:
- The user may be sent an e-mail message for each fax received, with the pages included as attachments, typically in either TIFF or PDF format.
- Incoming faxes may be stored in a dedicated file directory, which the user can monitor.
- A website may allow users to log in and check for received faxes.
- Special client software may be used.
Advantages over paper fax machines
- Users can send and receive faxes without leaving their desks.
- Any printable computer file can be faxed, without having to first print the document on paper.
- The number of fax lines in an organisation can be reduced, as the server can queue large numbers of faxes and send each when any of a number of lines is free.
- Faxing capability can be added easily to computer programs, allowing automatic generation of faxes.
- Transmitted faxes are more legible and professional-looking.
- There is less clutter of office equipment; incoming faxes can be printed on a standard computer printer.
- Printer jams on malfunctioning fax printers may be reprinted without being re-faxed.
- Faxing may be monitored and/or recorded, so that users may be allocated quotas or charged fees, or to ensure compliance with data-retention and finacial laws.
- Fax Servers can be located centrally in an organisation's data centres providing resilience and Disaster recover facilities to a traditionaly desktop technology.
- Incoming junk faxes are not as much of a problem; the server may maintain a blacklist of numbers it will not accept faxes from (or a white list listing all the numbers it will accept calls from), and those that do get through do not waste paper.
Public fax services
There are many companies (internet fax providers
) operating fax servers as a commercial public service. Subscribers can interact with the servers using methods similar to those available for standard fax servers, and would be assigned a dedicated fax number for as long as they maintain their subscription. Fees are normally charged on a flat monthly rate, with a limit on the number of fax pages sent and/or received. Organizations, and individuals in particular, may find this more convenient or cost-effective than operating their own fax systems.
Integrated fax programs
An integrated fax program is a complete set of faxing software which operates on a single computer which is equipped with a fax-capable modem connected to a telephone line. Its user interfaces may be similar to those used to communicate with fax servers, except that since the entire operation takes place on the user's computer the user may be made more aware of the progress of the transmission. Integrated fax programs are aimed at consumers and small organizations, and may sometimes be bundled
with the computer's operating system.