A teleprinter (teletypewriter, Teletype or TTY) is a electromechanical typewriter that can be used to communicate typed messages from point to point and point to multipoint over a variety of communication channels that range from a simple electrical connection, such as a pair of wires, to the use of radio and microwave as the transmission medium. They could also serve as a command line interface to early mainframe computers and minicomputers, sending typed data to the computer with or without printed output, and printing the response from the computer.

The salient features of teleprinter are listed below:

  1. A teleprinter is a telegraph transmitting receiving machine.
  2. Teleprinter resembles a typewriter because it has a typewriter like keyboard.
  3. A teleprinter is a mechanical device driven by electrical motors, recently Electronic machine has been introduced, controlled by the microprocessor.
  4. Code used by teleprinter machine is the 5-unit code,
  5. A teleprinter works on the start-stop principle.
  6. A teleprinter acts both as a transmitter and as a receiver.
  7. When used as a receiver, the signals are received in the serial form are converted into Parallel. Then a detector converts it into the character and the printer prints it on the paper.
  8. Every teleprinter has also the facility of local record,
  9. The actual mechanical arrangement of a teleprinter machine is  very Complicated, but a block diagram is shown in the figure. Which shows the different parts of the machine.
Teleprinter Block Diagram
Teleprinter Block Diagram

Application of the Teleprinter

  1. The teleprinter is basically used for sending and receiving of Telegraph signals,
  2. Teleprinter switching system is used in Telex (teleprinter exchange) which is a convenient method of sending printed  messages. An auto- telex service has the advantage of communication as in telephone astern and transfer of written record as in telegraph system.
  3. Due to these two advantages, these services are used both for commercial and industrial purposes,
  4. The teleprinter can also be used for typing the local records.