VT220
Encyclopedia
Computer terminal
A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system...
produced by Digital Equipment Corporation
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
from 1983 to 1987.
Hardware
The VT220 improved on the earlier VT100VT100
The VT100 is a video terminal that was made by Digital Equipment Corporation . Its detailed attributes became the de facto standard for terminal emulators.-History:...
series of terminals with a redesigned keyboard, much smaller physical packaging, and a much faster microprocessor. To meet the needs of various national regulatory agencies, the VT220 was available with CRT
Cathode ray tube
The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...
s that used white, green, or amber phosphor
Phosphor
A phosphor, most generally, is a substance that exhibits the phenomenon of luminescence. Somewhat confusingly, this includes both phosphorescent materials, which show a slow decay in brightness , and fluorescent materials, where the emission decay takes place over tens of nanoseconds...
s.
Several of the VT2xx models were pyramid shaped, allowing them to sit on a table top, leaving the surface of the display at an angle to the user; this angle could be adjusted. Because it was lower than head height, the result was an especially ergonomic terminal. The LK201
LK201
The LK201 was a detachable computer keyboard introduced by Digital Equipment Corporation of Maynard, Massachusetts in 1982. It was first used by Digital's VT220 ANSI/ASCII terminal and was subsequently used by the Rainbow-100, DECmate-II, and Pro-350 microcomputers and many of Digital's computer...
keyboard supplied with the VT220 was one of the first full length low profile keyboards available; it was developed at DEC's Roxbury
Roxbury, Massachusetts
Roxbury is a dissolved municipality and current neighborhood of Boston, Massachusetts, United States. It was one of the first towns founded in the Massachusetts Bay Colony in 1630, and became a city in 1846 until annexed to Boston on January 5, 1868...
, Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
facility.
The VT240 and VT241 were variants of the VT220, both capable of displaying vector graphics
Vector graphics
Vector graphics is the use of geometrical primitives such as points, lines, curves, and shapes or polygon, which are all based on mathematical expressions, to represent images in computer graphics...
. The VT241 was equipped with a color screen. The successor of the VT220 was the VT320, itself followed by the VT420
VT420
The VT420 was a computer terminal designed by Digital Equipment Corporation . Introduced in 1990, it fit up to 50 lines on the screen and supported two sessions, either one through each communication port, or by multiplexing two sessions on one line with a suitable terminal server...
.
Software
The VT220 was designed to be compatible with the VT100VT100
The VT100 is a video terminal that was made by Digital Equipment Corporation . Its detailed attributes became the de facto standard for terminal emulators.-History:...
, but added features to make it more suitable for an international market. This was accomplished with the National Replacement Character Set feature (e.g., Multinational Character Set
Multinational Character Set
The Multinational Character Set is a character encoding created by Digital Equipment Corporation for use in the popular VT220 terminal. It was an 8-bit extension of ASCII that added accented characters, currency symbols, and other character glyphs missing from 7-bit ASCII...
) and support for 8-bit downloadable character sets.