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Model M keyboard

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This is an old revision of this page, as edited by Icrosson (talk | contribs) at 21:25, 24 December 2008 (The former 'Model Ms' is incorrect grammar and led to a parse error when I read it, the replacement "Model M keyboards" is better.). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

IBM Model M Keyboard, Part no. 1391401, Manufactured 1989
Unicomp Customizer 104 (UNI0P46) keyboard, manufactured April 25, 2005.

The Model M keyboard is a class of computer keyboards manufactured by IBM, Lexmark and Unicomp, starting in 1984. The many different variations of the keyboard have their own distinct characteristics, with the vast majority having a buckling spring key design and many having fully swappable keycaps. Model M keyboards have been prized by computer enthusiasts and heavy typists because of the tactile and auditory feedback resulting from a keystroke.

The Model M is also regarded as an extremely durable piece of hardware. Many units manufactured since the mid 1980s are still in use today, while the computers and monitors of the day are obsolete. Unicomp, which now owns the rights to the design, now sells the keyboards.

History

Keycap in a French Model M

Production for the original Model M began in 1984, and the keyboards were often bundled with new IBM computers in the 1980s. These keyboards were produced by IBM, many were made in the United States, and many had part number 1391401. Until 1987, the keyboards featured a detachable AT cable; after that, they were bundled with a detachable PS/2 cable. Cables came in both 5- and 10-foot lengths.

In March of 1991, IBM divested a number of its hardware manufacturing operations, including keyboard manufacturing, to the investment firm Clayton & Dubilier, Inc. in a leveraged buyout to form Lexmark International, Inc.[1][2] The Model M keyboard continued to be produced by Lexmark in the United States, Mexico, Brazil, and Scotland with IBM being the major customer.[3] Many of the keyboards had IBM part number 52G9658, 83G2383, 42H1292, and others. Because of pricing pressures, many of these Model M keyboards were manufactured with a new lower-cost keyboard design to improve its competitiveness in the keyboard business.[4] Integrated keyboard cable and uniform print color on the keys were among some of the changes made.

In 1996, a company called Unicomp bought the Model M design from Lexmark. The keyboard, similar to part number 42H1292 but renamed 42H1292U, is still in production. Different configurations can be purchased from Unicomp, including updated 104/105-key layouts, a "Linux" model (where the Ctrl and Caps Lock keys, and the ESC and tilde keys, are swapped), models with integrated Trackpoint pointing sticks, and POS-specific models, such as those with built-in magstripe readers. Although current Unicomp models may be purchased for roughly 69 USD, original production models retain their value well among collectors as well as computer enthusiasts, and it is not uncommon to see them selling for upwards of 150 USD for a single, used unit.

There are numerous flavors of the Model M, but many of them are exceedingly rare. Sometimes it may be problematic to get them to communicate properly with a modern computer. A PS/2 to USB adapter would be necessary for computers without PS/2 ports, and the AT Model Ms additionally require an AT to PS/2 adapter. Some PS/2 to USB adapters are unreliable because the Model M tends to draw more power than some adapters expect. In response to these complaints, Unicomp added USB models to their lineup.

Design

Illustration from original U.S. patent 4,118,611, issued to IBM in 1978

The model people commonly refer to when they mention "Model M" is Part No. 1391401, which was by far the most common. This enhanced keyboard model included the patented buckling spring design[5] and swappable keycaps, as well as the heavy and sturdy design of the Model Ms in general. This keyboard is widely praised as being well-built. Part of this can be attributed to the fact that keyboard design has changed little in the past twenty years, while the designs of everything from PCs to monitors to mice have changed dramatically. The sturdy design (including heavy steel backplates and a high-quality, strong plastic frame) of the keyboard allows even the most abused to survive these years with ease. The various models of the keyboard had small differences, while keeping the style of the key mechanism that makes the boards unique. The 1391472 model, for example, does not have a separate number pad, rather it incorporates a number pad into the body of the main keys as many laptop keyboards do. Likewise, the early 1390120 series did not feature LED indicators for the locking keys.

Most fans of the Model M especially prize its feel and sound. Unlike the common (but cheaper) dome switch design in use today, the Model M's buckling spring design gives users obvious tactile (a distinctive resistance as the keys are depressed) and aural (a characteristic, loud "click-clack") feedback while typing, in ways similar to that of the keyboards of the long-running IBM Selectric typewriter line. In addition, the Model M keyboard is less susceptible to dirt and wear and tear; while dirt will interfere with proper operation of a dome switch keyboard, the design of a buckling spring keyboard is such that any dirt that falls between the cracks usually fails to make it into the spring mechanism. Failure of the mechanism to operate properly would require a large amount of accumulation, which is unlikely to occur.

There are some drawbacks to the Model M design, however. Because the keyboard is so heavy, it is not as portable as many modern keyboards. The keys are very noisy and would be inappropriate in a situation (such as a public library) where noise is an issue. Also, any liquids spilled on the keyboard would not drain out, and would remain in the keyboard with potential to cause a short circuit. The 42H1292 design and post-1993 1370477s and 1391401s, mostly made by Lexmark and Unicomp, includes drainage channels to prevent this, though it is done at the expense of a slight reduction in the keyboard's overall quality.

Identification

The square aluminum badge on a 1390131 series keyboard from 1986

All Model M keyboards manufactured by either IBM or Lexmark feature an ID label on the underside indicating the assembly part number, individual serial number, and date the keyboard was minted. There are other more obvious ways to distinguish between the range, namely the type of badge featured on the top of the keyboard. The first model Ms (part numbers 1390120 or 1390131) featured a square aluminum IBM badge in the top right corner. Part number 1391401 featured an oval, white IBM logo with grey lettering in the top left of the board. The later IBM manufactured keyboards and subsequent Lexmark keyboards of the early 1990s (part numbers 1370477, 52G9658, 92G7453, 83G2383, 42H1292, and others) featured a similar oval badge to part number 1391401, but instead with a grey background and blue lettering.

Features by part number

Part Number Key Type Detachable Interface Drainage Channels Label Type/Position Manufacturer Dates of Manufacture Copyright Misc features
Key Caps Cable
1370477 Buckling spring No Yes PS/2 Yes Blue, left corner Lexmark ?-1995-? Lexmark International, Inc. 1984
1370478 Buckling spring Yes Yes PS/2 Yes Blue, left corner Lexmark 1993 Lexmark Int'l. Inc. 1984 M-5, trackball. Left and right click, and L/R "drag" buttons.
1389979 Buckling spring Yes Yes AT No Silver, right corner IBM 1986–1987 IBM Corp. 1984 No LED lights for Num/Caps/Scroll lock. Swedish layout.
1390120 Buckling spring Yes Yes AT No Silver, right corner IBM 1986–1987 IBM Corp. 1984 No LED lights for Num/Caps/Scroll lock
1390131 Buckling spring Yes Yes AT or PS/2 No Silver, right corner IBM 1986–1987, 1993 IBM Corp. 1984
1390133 Buckling spring Yes Yes AT or PS/2 No Silver, right corner IBM ?-1986-1987 IBM Corp. 1984 German QWERTZ layout
1391401 Buckling spring Yes Yes AT or PS/2 No (yes 1993 and after) Grey (Blue 1992 and after), left corner IBM 1984–1996 IBM/Lexmark International Corp. 1984
1391402 Buckling spring Yes Yes PS/2 Yes ? Blue, left corner IBM UK ?–1993–1996-? IBM Corp. 1985 French AZERTY layout
1391403 Buckling spring Yes Yes AT or PS/2 No Grey, left corner IBM UK/Lexmark International 1986–1994 IBM Corp./Lexmark International Inc. 1985 German QWERTZ layout
1391404 Buckling spring Yes Yes AT or PS/2 No Grey, left corner IBM UK 1986–? IBM Corporation (no year on label) Italian QWERTY layout
1391405 Buckling spring Yes Yes AT or PS/2 No Black/Blue, left corner IBM 1986–? IBM Corp. 1985 Spanish QWERTY layout
1391406 Buckling spring Yes Yes AT or PS/2 No Grey, left corner IBM ≤1985–1996 IBM United Kingdom UK 102-key variant
1391407 Buckling spring Yes Yes PS/2 Yes Grey, left corner IBM ?–1996-? IBM United Kingdom Danish/Icelandic 102-key
1391409 Buckling spring Yes Yes PS/2 No Gray, left corner IBM 1989-1992? IBM Corp. 1985 Norwegian 102-key
1391410 Buckling spring Yes Yes PS/2 (or AT?) No ? IBM UK ?–1992–? IBM Corp. 1985 Portuguese 102-key
1391411 Buckling spring Yes Yes AT or PS/2 No Gray/blue, left corner IBM UK ?-1987–1997–? IBM Corp. 1985 Swedish 102-key
1391414 Buckling spring Yes Yes PS/2 (or AT?) No ? IBM UK ?–1996–? IBM Corp. 1985 Belgian AZERTY layout
1391412 Buckling spring Yes Yes PS/2 No Gray, left corner IBM UK 1987-1990-? IBM Corp. Swiss French/German QWERTZ layout, 102-key
1391472 Buckling spring Yes Yes AT or PS/2 No Gray, left corner IBM 1987-1991 IBM Corp. 1984 Space saver; no numeric keypad or lights
1391506 Buckling spring Yes Yes PS/2 No ? IBM de Mexico 1990 IBM Corp. 1984
1391511 Buckling spring Yes Yes PS/2 No Blue, left corner IBM UK 1992-1993 IBM Corp. 1985 Dutch 102-key
1393464 Buckling spring Yes Yes PS/2 No{?} Grey, left corner IBM ?-1987-1989-? IBM Corp. 1984 Same as 1391401, with special key-caps: Used for airline reservations
1393669 Buckling spring Yes Yes PS/2 No Blue, left corner Lexmark UK / IBM UK 1995 Lexmark International Inc. 1985 / IBM Corp. 1985 Croatian QWERTZ layout; speaker grill on bottom of unit
1394064 Buckling spring Yes Yes PS/2 No ? Lexmark ?–1996–? Lexmark International, Inc. 1984
1394540 Buckling spring No Yes PS/2 No Gray, left corner IBM 1990-09-24 IBM Corp. 1984 Made for IBM RS/6000 computer. Contains real speaker.
1394542 Buckling spring Yes Yes PS/2 Yes Gray, left corner IBM UK 1991-1994? IBM Corp. 1985 German QWERTZ layout
1394966 Buckling spring Yes Yes PS/2 ? Silver on black, left corner IBM UK 1992-02-13 IBM Corp. 1985 Swedish 102-key, dark gray industrial version
1395300 Buckling spring No No PS/2 No Blue, top right right IBM 1990-1993 IBM Corp. 1984 Model M2; Shipped with IBM PS/1
1396790 Buckling spring Yes No PS/2 Yes Blue, top left IBM ?-1992-1995? IBM Corp. 1985 Made in UK by IBM; North American layout
1397003 Buckling spring Yes Yes PS/2 ? Blue, top left IBM ?-1993-1999? IBM Corp. 1985 Made in UK by IBM; German QWERTZ; 122 Keys
1397599 Buckling spring Yes Yes PS/2 Yes Gray, left corner IBM ?–1993–? IBM Corp. 1984
1397681 Buckling spring No Yes PS/2 (or AT?) Yes Blue, left corner IBM ?-1992-? IBM Corp. 1984 Space saver; no numeric keypad or lights
1399625 Buckling spring Yes No PS/2 Yes Blue, left corner Lexmark, IBM UK ?-1994-? Lexmark International Inc. 1985 Terminal keyboard; speaker grill on bottom of unit; no lights
42H1292, 92G7453, 92G7483 Buckling spring Yes No PS/2 Yes Blue, left corner Lexmark, IBM UK 1993–1999 Lexmark International, Inc. 1984
71G4621 ? (non-clicky) Yes No PS/2 Yes Blue, left corner Lexmark (for IBM) ?-1996-? Lexmark International, Inc. 1984 Danish QWERTY layout
71G4625 Buckling spring Yes No PS/2 Yes Grey, left corner Lexmark (for IBM) ?-1993-? Lexmark International, Inc. 1984 German QWERTZ layout
82G2383 Buckling spring Yes No PS/2 Yes Blue, left corner Lexmark 1993–1999 Lexmark International, Inc. 1984
51G8572 Buckling spring Yes Yes PS/2 Yes Blue, left corner Lexmark, IBM UK 1993-1996 IBM Corp. 1984/Lexmark International, Inc. 1984 Model M; shipped with IBM RS/6000; speaker on bottom of unit
52G9658 Buckling spring Yes No PS/2 Yes Blue, left corner Lexmark ?-1993-? Lexmark International, Inc. 1984 Model M; speaker grill on bottom of unit
52G9700 Buckling spring Yes No PS/2 Yes Blue, left corner Lexmark 1993–1999 Lexmark International, Inc. 1984
71G4643 Dome switches Yes No PS/2 Yes Blue, left corner Lexmark ?-1995-? Lexmark International, Inc. 1985
71G4644 Dome switches No No PS/2 Yes Blue, left corner Lexmark ?-1993-1995-? Lexmark International, Inc. 1984
42H1292U Buckling spring Yes No PS/2 Yes ? Unicomp 1996–present Unicomp, Inc. 1984 Optional AT/DIR adapter
82G3281 Buckling spring No No PS/2 Yes ? Lexmark 1994–1995 Lexmark International, Inc. 1984 White trackpoint, two connectors for keyboard and mouse
13H6705 Buckling spring No No PS/2 Yes Silver, left corner Lexmark 1995–1998 Lexmark International, Inc. 1984 Trackpoint, two connectors for keyboard and mouse, the only Model M to come in Black
06H4173 Buckling spring No No PS/2 Yes ? Unicomp 1998–1999 Unicomp, Inc. 1984 Industrial PS/2 trackpoint, two connectors for keyboard and mouse
UB40R46 Buckling spring Yes No PS/2 Yes ? Unicomp ?–Present Unicomp, Inc. 1984 104 key, customizable layout.
UB4044A Buckling spring Yes No USB Yes None Unicomp ?–Present Unicomp, Inc. 1984 104 key, customizable layout (USB version).
02K3817 Buckling spring Yes No PS/2 Yes None Unicomp ?-Present Unicomp, Inc. 1984 German layout unicomp keyboard
Part Number Key Type Detachable Interface Drainage Channels Label Type/Position Manufacturer Dates of Manufacture Copyright Misc features
Key Caps Cable

Note: The manufacture dates are approximate.

See also

References

  1. ^ "IBM Archives: 1991".
  2. ^ "The Executive Computer; Can I.B.M. Learn From a Unit It Freed?".
  3. ^ "Keyboard vendors punched on prices".
  4. ^ "Lexmark International Reports Best Year Ever Since Independent of IBM".
  5. ^ US patent 4118611, Richard Hunter Harris, "Buckling Spring Torsional Snap Actuator", issued 1978-10-03  — an IBM patent for buckling spring keys.
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