Terminal (computer)

on-line terminal in Egypt
serial text terminal

a terminal of a computer is a user terminal to the input and expenditure of data.

function range

terminal were developed, in order to make for users possible direct access to a distant computer - they attained their furthest spreading accordinglyin the time of the large central computers. Before there were terminals with screen, teleprinters were usually used for communication with the computer. This very day the abbreviation is pervasive „tty “for the English counterpart „teletype “ in UNIX - operating systems and appropriate software. Off approx. 1977 graduallyusing spreading of single place computers (PC) displaced the terminals from most offices. Terminals are however common until today in other ranges.

Terminals are attached over local cable or a network to the computer. They are equipped with a special function range, ofthe use is dependent. Thus there are generally in offices applicable terminals with alphanumeric keyboard for the input and screens or printers for the expenditure. These terminals were replaced predominantly by terminal emulations, which run on a PC.

One differentiates between text and diagram terminals. First can represent only the indications and letters of a certain character set ( frequent ASCII), which are arranged in a matrix from usually 80 columns (as many as punch cards had) and 24 or 25 lines. The advantage of the use of a screen compared with teleprinters is in the fact that sequentially lines cannot only be spent, to change but that the arbitrary Manövrierbarkeit permits it to the cursor, text again and shift lines (scrolling).

The clearly more complex diagram terminals were developed primarily by Tektronix. They were the forerunner used of the today pixel-oriented hardware. However there were terminals also vector-oriented contrary to today, with which the electron beam was freely programmable in the cathode ray tube. It became the picture thus not from a memory (today: Diagram map), which was very expensive, selected and line for line and pixelfor pixels on the screen transfers, but the lines were written directly on the phosphorus layer, whereby in the memory only coordinates of the lines were to be reproached.


For individual industries there are industry-specific terminals:

  • Bank terminal
  • point-of-sale terminal
  • terminal for the factory data capture

of examples of terminals:

industry-specific terminals:

see also

 

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