Computer terminal

Computer terminal

A computer terminal is an electronic or electromechanical hardware device. It is used for entering data into, and displaying data from, a computer or a computing system. Early terminals were teletypess (TTYs), later ones use a Visual Display Units (VDU). Typically a terminal communicates with the computer via a serial line, often using the RS232 protocol.

Later, so called intelligent terminals were introduced, such as the VT100 and VT102, which are still widely emulated in software.

Most terminals were connected to Mainframe computers and often had a green or amber screen. A very small number of terminals with a few colors were created prior to the widespread introduction of the CRT.

While IBM PCs had single color green screens, these would not have been considered terminals. They could, however, emulate a terminal, if connected to a mainframe computer.