Fax

We explain what a fax is, how it works and what a virtual fax is. In addition, we tell you how it originated and why it stopped being used.

What is a fax?

A fax, telefax or telecopy is a type of telecommunications technology that was very popular in the second half of the 20th century, and that allowed both text and images of a scanned document to be transmitted by telephone and reproduced at the destination . For this, devices known as fax machinescapable of digitizing and printing documents.

“Fax” is the abbreviation for facsimilethat is, the almost exact reproduction of a book, drawing or document. It is an appropriate term to describe these devices, since operated by converting text into an image, similar to a photocopy for subsequent transmission through electrical impulses over the telephone line. The latter is why companies or organizations had a number exclusively dedicated to receiving documents by fax.

Fax technology was very much in vogue before the digital revolution of the late 20th century and early 21st century, and long before the smartphones. Its implementation allowed the rapid and efficient transmission of documents over long distances connecting business headquarters and users when email did not yet exist. Currently, fax is considered an obsolete technology, although it is still used in many places, although in modern versions that operate in conjunction with the Internet.

Origin and history of the fax

The antecedents of contemporary fax technology date back to the mid-19th century, when the telegraph made its entry into the Industrial Revolution. The first models of facsimile transmitters were designed in Great Britain and France. The first was carried out by the Scottish mechanic Alexander Bain in 1843, although his invention was never publicly demonstrated, while In London, in 1851, the first facsimile transmission was carried out using a system designed by the English physicist Frederick Bakewell .

The first long-distance fax transmission occurred in 1863 and was the work of Italian inventor Giovanni Caselli who managed to transmit a document from Lyon to Paris in France. However, it used much more primitive systems than those used in the 20th century. Subsequently, In 1902, the German Arthur Korn managed to transmit not only text but images, using selenium photocells and his invention was used to transmit newspaper photographs between Munich and Berlin, via telegraph circuits.

The appearance of the fax associated with the telephone line had to wait for the latter to be implemented massively. Between 1920 and 1923, the American company AT&T invested its efforts in this technology and managed, in 1924, to create a “telephotographic” machine which allowed photographs to be sent between Cleveland, Ohio and New York, through the telephone line. Although the resolution of these devices was poor and the transmission was slow (7 minutes on average), their appearance opened the door to a new range of office devices that between 1930 and 1960 they began to be mass produced .

Thus, starting in the following decade, fax machines themselves began to exist and be used. Since then, four fax “groups” can be distinguished, that is, four generations of devices dedicated to this type of transmission:

• Group 1 . It includes fax machines created around 1974, equipped with a vertical resolution of 98 lines per inch. They took between four and six minutes to transmit the scanned page and did so at about 2,400 bps.
• Group 2 . It includes fax machines created around 1976, as an improvement on those of the first group. They increased their resolution to 100 lines per inch and their transmission speed to 9600 bps, but they still took about 3 minutes per page.
• Group 3 . It includes fax machines created around 1980, capable of transmitting a single page in about 6 to 15 seconds, at an average speed of 14,400 bps and different standard resolution settings, between 100 and 400 lines per inch.
• Group 4 . It includes fax machines created after 1984, the only ones capable of operating on digital networks and therefore the only ones that are still used and manufactured. They are capable of operating at more than 64,000 bps.

Fax operation

The operation of a fax machine can be understood as the integration of a scanner, a laser printer, a telephone and a modem into a single device.

To transmit a document, fax machines must first contact each other and synchronize, for which it is necessary to type the telephone number; The document is then introduced through the upper end of the device where a roller takes it and makes it pass in front of the optical reader that reproduces it in a digital image .

This image is then transmitted through telephone pulses or digital internet signal, received by the destination device and reproduced (printed) for the latter. Today, the scanned fax image can also be stored on a computer system, such as a telephone or computer.

Thus, a fax machine can fulfill the following functions:

• Digitize and transmit a document or image over long distances, using a telephone line or Internet signal.
• Reproduce a document through laser printing, as if it were a photocopier.
• Convey documentation in a very secure way, being analog (and therefore neither hackable nor crackable).

When did faxes stop being used?

The fax lost ground immensely to email and the internet throughout the 1990s and 2000s . Currently it is considered a practically obsolete technology, although many companies continue to use it, especially for legal purposes since the content transmitted from fax to fax cannot be tampered with.

What is a virtual fax?

It is known as a virtual fax or internet fax to a online service for faxing documents over the Internet, without requiring a fax machine nor enjoy its modest virtues.

Through a virtual fax, documents can be transmitted via email or a web page, without using up the telephone line or spending money on printing paper. Instead, transmission software and documents in .doc, .pdf or other formats are used. The virtue of this type of program is that can be received and sent on a traditional fax machine .

References

• “Virtual fax” on Wikipedia.
• “How did faxing documents work?” (video) on TV Azteca (Mexico).
• “How does a fax machine work?” at the College of Public Calligraphers of the City of Buenos Aires (Argentina).
• “Fax (communications)” in The Encyclopaedia Britannica.