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LK201AA top.jpg
Manufacturer DEC
Layouts 105-key DEC "ANSI Layout" (aka. VMS Layout)
Interface RS423, 4800 bps
Introduced 1982

The DEC LK201 keyboard was made by Digital Equipment Corporation (DEC) for the DEC VT-220 terminal. Several succeeding terminals and workstations from DEC were compatible with this keyboard, and there were several compatible clones from other manufacturers.


The LK201 is a membrane keyboard. Keycaps with cruciform pegs sit within a plastic assembly, and operate metal springs that press down on the membrane.[1]


The layout of the LK201 has been very influential on subsequent systems. The main typing area has what later became the ISO layout, a QWERTY keyboard with a vertical Enter key, Tab to the left of 'Q' and a '<' key to the left of 'Z'. Like its predecessor, the keyboard for the VT102, both the control and caps lock keys are to the left of 'A'. The break and delete keys were moved slightly to the right into a new group of keys, so that there was space to the right of the enter key.

Function keys are on a top row, separated into several groups. There is also a numeric keypad on the right side with four additional function keys.

The LK201 was also (one of) the first keyboards to have a compose key, which was situated to the left of the space bar.

Inverse T

Inverse-T layout introduced by the LK201

The LK201 is most famous for being the keyboard that popularised the inverse-T cursor key arrangement. While the LK201 was not the first keyboard to use this arrangement, it was chosen after serious studies into usability.[2] Whether the design was independently re-invented, or copied from an earlier keyboard, is not known.


DEC, being a major player in the computing industry in the 1980s inspired many successors with its keyboard layouts. It was especially the inverse-T cursor keys that caught on.

The location of cursor keys, the delete key and function keys are almost the same on the IBM Enhanced Keyboard (Model M), but the cursor keys have been moved one row down. The keyboard layouts of the Amiga and Atari ST keyboards have also been greatly inspired by the LK201 and the VT102 layout.


There are many variants of the LK201 for localization and other purposes. The keyboard code contains a two character suffix indicating the variant. For example, the LK201-AA is the USA/UK variant. There was a variant with APL keycaps, the LK201-EC.


Many keyboards copied the LK201 layout outright:





  1. Soretonaku Keyboard — 解体新書DEC LK201 Keyboard
  2. Tim Burrows. "Inverse-T History", The Nerd Corner. Sep 21, 2009. (Acquired May 22, 2012)

External links