Which of the following is used for input and output both?
Teletype terminal is used for input and output both.
A teleprinter (teletypewriter, Teletype or TTY) is an electromechanical typewriter that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. The machines were adapted to provide a user interface to early mainframe computers and minicomputers, sending typed data to the computer and printing the response. Some models could also be used to create punched tape for data storage (either from typed input or from data received from a remote source) and to read back such tape for local printing or transmission.
A teletypewriter (TTY) is an input device that allows alphanumeric character to be typed in and sent, usually one at a time as they are typed, to a computer or a printer. The Teletype Corporation developed the teletypewriter, which was an early interface to computers. Teletype mode is the capability of a keyboard, computer, application, printer, display, or modem to handle teletypewriter input and output. Basically, this is a one-character-at-a-time mode of sending, receiving, or handling data, although it is often modified to handle a line of characters at a time. Since this mode requires little programming logic, it is often used where memory is limited. The Basic Input/Output Operating System ( BIOS ) sends messages to a PC display using teletype mode. Most printers offer a teletype mode. The simplest video display output format is text in teletype mode. Many modems today continue to include support for a TTY interface.