Teletypes, sometimes spelled as teletypewriters, are machines used for transmitting and receiving typed messages over a distance. Common synonyms for teletypes include teleprinters, telewriters, and telex machines. The term "teleprinters" is often used to describe the machines used for sending and receiving text-only messages, while "telewriters" more specifically refers to machines designed for typing and printing. "Telex machines" are a type of teleprinter that were widely used for telecommunications in the 20th century, and can be interchangeable with the term teletypes. Regardless of terminology, these machines played an important role in early communication technology and paved the way for modern communication methods.