Teleprinter

WACsOperateTeletype

Dag Hammarskjöld - ASCII - teleprinter art -1962

Printing Telegraph

Siemens t37h without cover

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International Telegraph Alphabet 2 brightened

Teleprinter (also known as a teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communication channels, including point-to-point and point-to-multipoint circuits. The teleprinter evolved from earlier telegraph systems and became a key technology in telecommunications and news agencies before the advent of computers and electronic messaging systems.

History

The development of the teleprinter can be traced back to the 19th century, with significant contributions from inventors such as Charles Wheatstone and Emile Baudot. Wheatstone's early version in the 1840s, and Baudot's code, developed in the 1870s, laid the groundwork for the technology. The Baudot code, a binary code that represented letters, numbers, and symbols, was particularly influential in the design of subsequent teleprinters.

In the early 20th century, the teleprinter began to gain widespread use, especially after the refinement of the start-stop synchronization method, which allowed teleprinters to synchronize transmission without the need for a continuous connection. This innovation led to the widespread adoption of teleprinters in various sectors, including journalism, government, and the military.

Operation

A teleprinter works by converting the keystrokes of the operator into electrical signals, which are then transmitted over a communication line to another teleprinter. The receiving teleprinter decodes these signals and prints the corresponding characters on paper. Early teleprinters used the Baudot code, but later models adopted the ASCII (American Standard Code for Information Interchange) code, which allowed for a greater range of characters and symbols.

Teleprinters were initially connected via dedicated telegraph lines, but they were later adapted to work over telephone lines, significantly expanding their reach and utility. Some teleprinters were equipped with punched tape readers and writers, allowing messages to be stored on tape for later transmission or printing.

Impact

The teleprinter had a profound impact on communication, particularly in fields that required the rapid transmission of text-based information. In journalism, teleprinters enabled the fast distribution of news stories to newspapers around the world. In finance, teleprinters were used to transmit stock market data. In the military, secure teleprinter networks were established for the transmission of sensitive information.

The technology also played a crucial role in the development of early computer networks. The ARPANET, a precursor to the modern Internet, initially used teleprinters as terminals. This allowed users to interact with computers and other users across the network.

Decline

With the advent of personal computers and electronic messaging in the late 20th century, the use of teleprinters declined. Modern technologies such as email, instant messaging, and SMS have largely supplanted the teleprinter. However, the legacy of the teleprinter lives on in certain applications, such as the TTY devices used by the deaf and hard of hearing community to communicate over telephone lines.

See Also

• Telegraphy
• Morse code
• Telex
• Fax