P/N 28L3640 - Model M4-1 Keyboard Details & Specs

Provided by the ASK Keyboard Part Number Database

IBM 84-Key Space Saver Keyboard with TrackPoint

FRU Part NumberFRU Part Number
Field Replaceable Unit
The number used to relate and indicate compatible but otherwise potentially different keyboards that could replace this one.
A designation from my own type naming scheme used to categorise this keyboard with or from others by their common features and market intent but may/may not be derived from official names.
Model M4-1 Space Saver TrackPoint II Keyboard
Possible companies responsible for making this keyboard for the company marketing it.
The name of the known switching mechanism that lies under this keyboard's keys.
IBM buckling rubber sleeves (M3/M4 rod-actuated type)
Earliest AppearanceEarliest Appearance
The year (and possibly the quarter) that this keyboard part number was introduced, first observed, first recorded or the first example found.
1998 Q3
Casing ColourCasing Colour
The original colour of this keyboard's outer casing. For keyboards whose casing materials are known to yellow, this will refer to the original colour before such transformation occurs.
Raven (Stealth) Black
The possible branding and logo styles found on this keyboard part number. This could be multiple styles at once or possible styles found over time.
IBM black oval badge
The style of this keyboard's flip-out or extendable feet. If applicable, this may also state how many levels of height adjustment are available and whether the feet could be rubberised.
Rubberised single-setting flip-out feet
The protocol(s) this keyboard can use to speak to the host computer (eg, scancode sets).
IBM Mode 2 (scancode set 2)
The keyboard-to-host connection. This is could be a description of a cable (its colour, whether its coiled, whether its detachable, and what connector is at its end) or the name of a wireless technology.
Black coiled-style detachable 6-pin SDL to dual mini-DIN PS/2 cable
Key CountKey Count
The number of keys that this keyboard originally had.
Form FactorForm Factor
The standardised or universally acknowledged name for this keyboard's layout form factor.
Tenkeyless (compacted)
Image of Layout/LanguageThe original regional/language layout this keyboard was configured as. Both the language and the standardised key layout may be listed, and in the case of both being known or defined, it will be styled as language then standard.
Built-In MouseBuilt-In Mouse
Possible pointing devices this keyboard could carry. This could be a brand name, name of the sensor technology behind it, or a generic description in lieu of the former details.
TrackPoint II strain gauge pointing stick
Additional NotesAdditional Notes
Extra notes about this keyboard that may be of interest or are important to know.
Designed for use with the IBM Netfinity Rack Keyboard Tray (P/N 28L4707)
Documents ("Doc"), websites and/or webpages ("Web") that were used as a source of information for this keyboard part number. Examples of this keyboard part number I own ("ASK") will also be included as sources.
Doc: IBM Space Saver Keyboard - Product Overview (#VLAR-3Z5GNH) [source: kev009]
Web: https://web.archive.org/web/19991006163825/http://www5.pc.ibm.com:80/us/products.nsf/$wwwPartNumLookup/_28L3640
Data Last Updated 2023-04-27

More on this type of keyboard...

Variant of a Model M4-1 Space Saver TrackPoint II Keyboard
Variant of a Model M4-1 Space Saver TrackPoint II Keyboard
Variant of a Model M4-1 Space Saver TrackPoint II Keyboard
Variant of a Model M4-1 Space Saver TrackPoint II Keyboard

The IBM Space Saver Keyboard with TrackPoint II (not to be confused with the IBM Space Saving Keyboard or SSK) was the discrete desktop and server environment adaptation of the IBM Personal System/2 L40SX laptop's Model M3-based buckling sleeves keyboard assembly. Compared to the standard Model M4, the M4-1 is a modified design that equips a TrackPoint II pointing stick. These M4-1s were notable for being the first IBM desktop keyboard to feature TrackPoint strain gauge technology and the only Model M to retain such a stick when produced by Unicomp. M4-1s were originally produced by Lexmark and Key Tronic, however, Unicomp continued selling M4-1s until 2008. Unicomp's internal codename for the M4 family was "Surf".