A fax server is software and hardware that allows many users to send and receive documents through one central fax system. The fax software runs on a computer frequently dedicated to the task of faxing. Its hardware includes one or more fax modems connected to telephone lines or an Internet Protocol (IP) network. Fax servers are used to lower costs and improve efficiency by organizations of all types. Some people have built entire businesses around charging others to send, receive and store faxes using their servers.
Fax server software collects documents to be faxed from multiple users. Often sent by email or uploaded through a web interface, they can be in one of several popular formats. Plain text, Portable Document Format (PDF) and common word processing software documents are generally accepted. Some fax servers also allow users to output documents directly to a virtual print device. This device then transfers the documents to the server without actually printing them.
Once received by the fax server, each document is converted to fax format and queued for transmission. One of possibly several stand-alone or card-based fax modems in the server computer transmits the document. When it is finished, a success or failure message may be sent by email, text message or other means to the original user.
A fax server also answers incoming fax calls and may screen them against a list of known "junk" fax senders. Documents received by the server can be stored in PDF or other common formats. The server may email a document directly or simply notify a user that there is a fax waiting.
Compared to traditional faxing, a fax server offers many advantages. No document printouts are needed, saving paper and toner. Documents are transmitted as soon as a fax modem is free, rather than when someone has time to fax them by hand. Received documents are available instantly and only by the intended recipient. Only one fax server is usually needed for a large organization, rather than many individual fax machines.
Paper jams and skipped pages are no longer problems with a fax server. Faxes may be more easily tracked and recorded if necessary. For maintenance, an Information Technology (IT) department can take responsibility for a centrally-located server. Automatic fax capability may be added or enabled in other types of software. A server can also deliver a fax to a Unified Messaging System mailbox instead of emailing it.
Some fax servers are designed to send and receive faxes directly over the corporate intranet. These use International Telecommunication Union (ITU) T.38 "fax over IP" technology instead of a telephone line. Internet fax services often provide convenient faxing and document storage for individual business owners. For a monthly fee, a user can have one or more fax numbers in different area codes with no phone lines required. Faxes are stored on a server and uploaded or downloaded as documents via the Internet.