Teleprinter
Introduction
A teleprinter, also known as a teletypewriter or TTY, is an electromechanical typewriter that can be used to send and receive typed messages through various communication channels. Teleprinters were widely used for business and government communication during the mid-20th century, particularly before the advent of modern digital communication technologies. They played a crucial role in the development of telecommunications and data transmission systems.
Historical Development
Early Innovations
The concept of the teleprinter can be traced back to the early 19th century with the invention of the telegraph. The telegraph allowed for the transmission of coded messages over long distances using electrical signals. However, the need for a more user-friendly and efficient system led to the development of the teleprinter.
In 1846, Royal Earl House invented the first printing telegraph, which could print messages directly onto paper. This invention laid the groundwork for subsequent advancements in teleprinter technology.
The Baudot Code
One significant milestone in the development of teleprinters was the creation of the Baudot code by Émile Baudot in 1874. The Baudot code is a character set that uses a series of five bits to represent each character. This code became the standard for telegraphy and was later adapted for use in teleprinters.
The Teletype Corporation
The Teletype Corporation, founded in 1906, played a pivotal role in the commercialization and widespread adoption of teleprinters. The company's Model 15, introduced in 1930, became one of the most popular and enduring teleprinter models. It was used extensively by news agencies, government offices, and businesses.
Technical Specifications
Electromechanical Components
Teleprinters are composed of several key electromechanical components, including:
- **Keyboard**: Used to input characters and commands.
- **Printer Mechanism**: Consists of a typewheel or typebar that strikes an inked ribbon to print characters on paper.
- **Paper Feed**: Moves the paper through the printer mechanism.
- **Electrical Circuits**: Control the transmission and reception of signals.
Communication Protocols
Teleprinters use various communication protocols to transmit and receive data. Some of the most common protocols include:
- **Baudot Code**: A five-bit code used for character representation.
- **ASCII**: The American Standard Code for Information Interchange, a seven-bit code that became widely used in later teleprinter models.
- **Morse Code**: An older code that was sometimes used in conjunction with teleprinters for specific applications.
Applications
News Agencies
Teleprinters were extensively used by news agencies to transmit news stories and updates. The Associated Press and Reuters relied on teleprinters to disseminate information quickly and efficiently to their subscribers.
Military and Government
Teleprinters played a crucial role in military and government communications. They were used for sending encrypted messages, coordinating operations, and maintaining secure lines of communication. During World War II, teleprinters were integral to the Allied communication network.
Business and Industry
In the business sector, teleprinters were used for a variety of purposes, including order processing, inventory management, and interoffice communication. They facilitated the rapid exchange of information between different branches and departments.
Decline and Legacy
With the advent of digital communication technologies, such as fax machines, email, and the internet, the use of teleprinters began to decline in the latter half of the 20th century. However, their legacy lives on in modern telecommunications and data transmission systems.
Teleprinters laid the foundation for the development of computer terminals and early modems, which paved the way for the digital communication revolution. The principles of encoding, transmitting, and decoding data that were pioneered by teleprinters continue to be relevant in contemporary communication technologies.