Teletypewriter

Teletypewriter

A teletypewriter (TTY) is a text-based communications device that transmits and receives typed characters over a communication channel, such as a telephone line or radio Link. It was widely used in the early to mid-20th century for telegraphy, teletypewriter networks, and computer terminals.

TTYs consist of a keyboard for inputting text, a display screen or printer for outputting text, and a telecommunication Interface (such as a modem) for transmitting and receiving data over a communication channel. They can operate in full-duplex mode (allowing for simultaneous transmission and reception) or half-duplex mode (allowing for communication in only one direction at a time).

TTYs use a standardized Code, known as the Baudot code, which assigns a unique 5-bit Binary Code to each character. This code is transmitted and received over the communication channel, and the receiving TTY decodes the code to reproduce the original text.

Applications

Teletypewriters played a significant role in the development of early communication systems, including telegraphy and computer terminals. They were widely used:

• Telegraphy: TTYs replaced Morse code as the primary means of transmitting telegrams, providing faster and more efficient communication.

• Teletypewriter Networks: TTYs formed the basis of teletypewriter networks (TWX), which allowed businesses and organizations to exchange typed messages over long distances.

• Computer Terminals: TTYs were used as terminals for early computer systems, allowing users to input commands and receive output via a text-based interface.

TTYs continue to be used today in niche applications, such as:

• Assistive Technology: TTYs are used by individuals with hearing or speech impairments to communicate via text-based devices.

• Telemetry: TTYs are used to transmit data from remote devices, such as weather stations or industrial sensors.

• Security: TTYs provide a secure means of communication, as the transmitted data is not easily intercepted or eavesdropped upon.

History

The concept of a teletypewriter dates back to the early 19th century, with inventors experimenting with various methods of transmitting text over long distances. However, it was not until the late 19th century that practical teletypewriters were developed.

• 1874: Emile Baudot invented a 5-bit code that became the basis for teletypewriter communication.

• 1902: Frederick G. Creed developed a commercially successful teletypewriter machine.

• 1920s: Teletypewriters gained widespread adoption for telegraphy and other communication applications.

• 1930s: Teletypewriter networks (TWX) were established, connecting businesses and organizations across the country.

• 1950s-1970s: TTYs were widely used as computer terminals, facilitating the development of early computer systems.

• 1980s-Present: Despite the advent of digital communication technologies, TTYs continue to be used in niche applications, particularly for assistive technology and security purposes.