A teletypewriter, often abbreviated as TTY, is a device that combines a typewriter and a telegraph. It allows users to send and receive typed messages over long distances using electrical signals. The messages are printed on paper, making it easier to communicate in real-time. Teletypewriters were widely used in the mid-20th century, especially in newsrooms and businesses. They played a crucial role in the development of early computer communication and paved the way for modern devices like fax machines and email. Although largely replaced by digital technology, TTYs are still used in some specialized fields today.