Model M keyboard
A durable buckling-spring keyboard influential on later layouts.
The Model M is a family of computer keyboards first built by IBM in 1985, with later production by Lexmark International, Maxi Switch, and Unicomp. Most versions use buckling-spring key switches and have a uniform keycap profile with swappable keys. Typists and computer enthusiasts prize them for their sturdy build, consistent feel, and the distinct tactile and audible feedback they provide.
The keyboard’s design became highly influential after the success of the IBM PC and its successors. Nearly all later general-purpose keyboards copied its key arrangement and ergonomic features. The layout was formalized by ANSI in 1988 and by ISO in 1994; later revisions of these standards added or allowed for small changes, notably the Windows key and Menu key.
The Model M is considered a classic and very durable piece of hardware. While the computers and peripherals sold alongside it are now obsolete, many Model M keyboards remain in use because they are physically tough and their ANSI 101-key and ISO 102-key layouts are still practical. Users connect them to modern computers via a PS/2-to-USB adapter that includes a built-in interface converter. New generations have discovered the keyboard’s unique feel and look long after its original popularity.
An estimated 10 million Model M units were shipped during the IBM and Lexmark years. Mass-market sales ended in the 1990s as the industry shifted to cheaper rubber dome over membrane keyboards. IBM stopped making the Model M in 1996.
**History**
The Model M was designed to be cheaper to produce than its predecessor, the Model F. Principal design work took place at IBM from 1983 to 1984, drawing on extensive user feedback, ergonomic studies, and analysis of competing products. Its key layout differed significantly from the Model F’s, borrowing heavily—including the inverted-T arrow key arrangement—from the LK-201 keyboard used with the VT220 serial terminal.
Production began in 1985. The keyboard first shipped with the 3161 terminal, though it is now mostly associated with the IBM PC and its successors. From 1986, the PC AT and PC XT came with the Model M, and it was also used across other IBM product lines, such as the 5250 terminal and the RS/6000.
Keyboards were made at IBM plants in Lexington, Kentucky; Greenock, Scotland; and Guadalajara, Mexico.
- Introduction year
- 1985
- Estimated total shipped
- over 10 million
- Original manufacturer
- IBM
- Later manufacturers
- Lexmark International, Maxi Switch, Unicomp
- Production ended by ibm
- 1996
- Common variant part number
- 1391401
- Key switch type
- buckling-spring (vast majority)
Lore & Background
The Model M keyboard was designed to be less expensive to produce than the Model F keyboard it replaced. Principal design work was done at IBM in 1983–1984, drawing on user feedback, ergonomic studies, and examination of competing products. Its key layout, including the inverted-T arrangement of its arrow keys, owed much to the LK-201 keyboard shipped with the VT220 serial terminal. Production began in 1985, and it first shipped with the 3161 terminal, later with the PC AT and PC XT from 1986. Keyboards were produced at IBM plants in Lexington, Kentucky; Greenock, Scotland; and Guadalajara, Mexico. The most common variant is the IBM Enhanced Keyboard, part number 1391401, bundled with the IBM Personal System/2. Until around 1993, most Model Ms included a coiled, detachable cable with AT or PS/2 connectors. From about 1994, flat non-detachable cables were used to reduce costs. IBM retained its 101-key layout, never implementing Windows keys. In 2000, Unicomp designed a 104-key Model M with Windows keys. In 2013, this variant was discontinued in favor of a variant replicating Topre's Realforce 103U, with only one Windows key on the left, and a variant with a shortened space bar for a second Windows key.
Reader's Guide
The Model M's design was influential due to the popularity of the IBM PC and its successors; almost all later general-purpose computer keyboards mimicked its key layout and other ergonomic aspects. The layout was standardized by ANSI in 1988 and ISO in 1994. Later versions of those standards specified or provisioned for minor additions, most notably the Windows key and Menu key. Although the computers and peripherals produced concurrently with the Model M are considered obsolete, many Model M keyboards remain in use due to their physical durability and the continued validity of their ANSI 101-key and ISO 102-key layouts, through the use of a PS/2-female-to-USB-male adapter with a built-in interface converter. New generations have discovered their unique functionality and aesthetics. The mass-market success of the Model M ended in the 1990s amid an industry-wide switch to lower-cost rubber dome over membrane keyboards. IBM stopped producing the Model M in 1996. Unicomp continued production using original IBM machinery, leading to a gradual decline in quality as tooling became worn, but in 2020 Unicomp replaced its tooling and shipped a 'New Model M' with improved build quality.
Did You Know?
- IBM never implemented the Microsoft Windows keys on its Model M keyboards.
- The Space Saving Keyboard variant integrated the number pad into the main section, likely originating the 'Tenkeyless' layout.
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