Fax modem

A fax modem enables a computer to transmit and receive documents as faxes on a telephone line. A fax modem is like a data modem but is designed to transmit and receive documents to and from a fax machine or another fax modem. Some, but not all, fax modems do double duty as data modems. As with other modems, fax modems can be internal or external. Internal fax modems are often called fax boards.

In the early 1990s small business PCs commonly had a PC-based fax/modem card and fax software (typically WinFax Pro). Largely replaced by email, PC-based faxing with a fax/modem declined at the turn of the century. Where faxing from a PC is required there are a number of Internet-based faxing alternatives. Where businesses still had one or more traditional fax machines churning out pages, they were usually outnumbered by PCs processing E-mail.

PC faxing

Computer users may set up a PC fax/modem with card, telephone line access and software. A special printer driver may be included to allow treating the fax modem as a printer. Fax integration is available in unified communications (e.g. E-mail, Voice Mail and Fax managed together), in a number of Hosted PBX products where standard features allow users to send a fax by using the fax phone number as the address of a E-mail message, and receive incoming faxes via E-mail with the Fax content presented as a PDF attachment.

Modem

A modem (modulator-demodulator) is a network hardware device that modulates one or more carrier wave signals to encode digital information for transmission and demodulates signals to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. Modems can be used with any means of transmitting analog signals, from light emitting diodes to radio. A common type of modem is one that turns the digital data of a computer into modulated electrical signal for transmission over telephone lines and demodulated by another modem at the receiver side to recover the digital data.

Modems are generally classified by the amount of data they can send in a given unit of time, usually expressed in bits per second (symbol bit/s, sometimes abbreviated "bps"), or bytes per second (symbol B/s). Modems can also be classified by their symbol rate, measured in baud. The baud unit denotes symbols per second, or the number of times per second the modem sends a new signal. For example, the ITU V.21 standard used audio frequency shift keying with two possible frequencies, corresponding to two distinct symbols (or one bit per symbol), to carry 300 bits per second using 300 baud. By contrast, the original ITU V.22 standard, which could transmit and receive four distinct symbols (two bits per symbol), transmitted 1,200 bits by sending 600 symbols per second (600 baud) using phase shift keying.

Hayes command set

The Hayes command set is a specific command language originally developed by Dennis Hayes for the Hayes Smartmodem 300 baud modem in 1981.

The command set consists of a series of short text strings which can be combined to produce commands for operations such as dialing, hanging up, and changing the parameters of the connection. The vast majority of dial-up modems use the Hayes command set in numerous variations.

The command set covered only those operations supported by the earliest 300 bit/s modems. When new commands were required to control additional functionality in higher speed modems, a variety of one-off standards emerged from each of the major vendors. These continued to share the basic command structure and syntax, but added any number of new commands using some sort of prefix character – & for Hayes and USR, and \ for Microcom, for instance. Many of these re-standardized on the Hayes extensions after the introduction of the SupraFAXModem 14400 and the subsequent market consolidation that followed.

Modem (disambiguation)

A modem is a device that encodes and decodes digital data transmitted by a telephone or other analog communications system.

Modem may also refer to:

See also

Fax

Fax (short for facsimile), sometimes called telecopying or telefax, is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer or other output device. The original document is scanned with a fax machine (or a telecopier), which processes the contents (text or images) as a single fixed graphic image, converting it into a bitmap, and then transmitting it through the telephone system in the form of audio-frequency tones. The receiving fax machine interprets the tones and reconstructs the image, printing a paper copy. Early systems used direct conversions of image darkness to audio tone in a continuous or analog manner. Since the 1980s, most machines modulate the transmitted audio frequencies using a digital representation of the page which is compressed to quickly transmit areas which are all-white or all-black.

History

Wire transmission

Scottish inventor Alexander Bain worked on chemical mechanical fax type devices and in 1846 was able to reproduce graphic signs in laboratory experiments. He received patent 9745 on May 27, 1843 for his "Electric Printing Telegraph."Frederick Bakewell made several improvements on Bain's design and demonstrated a telefax machine. The Pantelegraph was invented by the Italian physicist Giovanni Caselli. He introduced the first commercial telefax service between Paris and Lyon in 1865, some 11 years before the invention of the telephone.

Fax (TV series)

Fax was a show by the BBC one, shown in the 1980s. It was presented by Bill Oddie, Wendy Leavesley, Debbie Rix and Billy Butler. The series first appear on Tuesday 7 Jan 1986 at 17.35, sharing its slot with Masterteam, Rolf Harris cartoon and sitcoms. Viewers would write in questions for the team to answered in each episode.

Fax third series was moved to a Sunday teatime slot, when Michael Grade moved the Australian soap Neighbours to the early evening.

Series

References

Links

Fax (Argentine TV show)

Fax was a 1991-1992 Argentine talk show, hosted by Nicolás Repetto. It received two Martín Fierro Awards for best host and best production, and the first Golden Martín Fierro Awards.