IBM Beam Spring Keyboards

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IBM's first generation electronic capacitive-coupled keyboards, known as the beam spring keyboards, were keyboards using the beam spring mechanism. These replaced special adaptations of the Selectric typewriter modified to communicate with a computer during the early 1970s.

Detachable Beamspring Keyboards


Launched in 1979, the 3101 was a low cost serial ASCII terminal designed to work with both IBM systems, and systems made by competing vendors. Its keyboard had the same physical key arrangement of the 87-key 3278 keyboards (or the 88-key Japanese layout), but featured a different housing and a different keycap colour scheme. IBM later produced a Model F version that was interchangeable with the beam spring one.



66 key version

Micro Switch

78 key version


The IBM 3278 Display Station keyboards were part of the 3278 Display Station which were terminals for IBM mainframes. They featured keyboards with 75 and 87-key layouts (76 and 88 for katakana), with different legends for various purposes.


The IBM 3279 was IBM's first colour terminal. It was introduced in 1979. It was part of the 3270 series, using the 3270 datastream.


The IBM 3727 Operator Console was a variant of the 3101 designed to be attached to the the IBM 3725 Communications controller. Aside from a slightly different layout, the keyboard appears to be identical to the 3101's one.


IBM 4978 keyboard (US version)

The IBM 4978 Display Station was a terminal for the IBM Series/1 minicomputer. It used a 122-key layout with 32 relegendable keycaps.


IBM 5251 keyboard (US version)
IBM 5251 keyboard with German keycaps

The IBM 5251 Display Station was part of the 5250, which were terminals for IBM mainframes. They featured keyboards with a 83- or 85-key (Katakana) layout, similar to the later 83-key System/23 Datamaster and IBM PC keyboards.


The IBM 5253 Display Station and the two-screen 5254 (not to be confused with the 5251 and 5252) were the terminals of the IBM 5520 Administrative System, which was designed to create and process documents. As with the later DisplayWriter, there were two layout options: an 82-key, 92-character keyboard; and an 84-key, 96-character keyboard. The keyboards appear to be largely identical to those of the DisplayWriter, except that they used dark keycaps with white legends.


The IBM 6580 DisplayWriter was a word processor introduced by IBM in 1980. It featured two keyboard configurations: 82-key (with 92 characters) and 84-key (with 96 characters). One unusual feature was that the Caps Lock key physically locked down when pressed. The keyboard also contained a speaker instead of the click solenoid found in other Beam Spring keyboards. The DisplayWriter was most likely the last IBM machine to feature a beam spring keyboard. The next year, IBM launched the System/23 Datamaster and the 5150 Personal Computer.


The IBM 7485 Display Station terminal is mentioned in certain documentation, and may have been a variant of the 3101.

Non-detachable Beamspring Keyboards




Launched in 1973, the IBM 3604 Keyboard Display keyboards were part of the IBM 3600 Financial Communication System, a set of terminals and printers for bank tellers, and the networking equipment required to interface them with an IBM mainframe. The 3604 keyboard displays were the 3600's terminals, there were six models of which Models 1 - 4 featured beam spring keyboards (Models 5 and 6 used smaller keys which, at least in later production examples, used rubber dome switches). Model 1 was a compact unit which could be equipped with one of three keyboard options:

  • A 30-key Numeric Keypad, which featured a 15-key numeric keypad, and another 15-key block whose functionality was determined by the system software.
  • A Data Entry layout, which was based on the Numeric Keypad.
  • A 45-key Extended Numeric Keypad, which added another 15-key programmable function block to the keyboard.

Models 2 - 4 were larger units which differed by screen size. There were two more keyboard options available in addition to the ones available for the Model 1:

  • A 74-key Alphanumeric layout, which featured an alphanumeric keypad with the same physical alphanumeric keypad layout as that on the 3277 78-key terminals. To the right of that was a numeric keypad and a number of programmable function keys. It is perhaps interesting to note that if one takes this layout, removes the Reset and Enter keys, replaces the Return and Back Tab keys with an ISO-style return, replaces the Tab and Lock key with a single L-shaped key the result is quite similar to the physical key arrangement of the later IBM 5100.
  • A 94-key Extended Alphanumeric layout, which added an additional 20 programmable function keys to the standard Alphanumeric layout.

The 3604 was replaced by the IBM 4704 which was launched in 1982. The 4704's Model F keyboard options are somewhat similar to those of the 3604.


The IBM 3741 Data Station keyboard, and the related IBM 3742 (which was effectively two 3741s integrated into the one desk back-to-back) were released by IBM in 1973. They were designed as a more modern (by the standards of the time) alternative to a keypunch by storing data on 8" floppy disks instead of punching holes onto card. The keyboard was somewhat similar in layout to that of the IBM 029 keypunch.


The IBM 3767 Communications Terminal keyboard was a printer type terminal from IBM which featured an integrated Beam Spring keyboard.


The IBM 4979 Display Station console was a terminal that was launched in 1976 alongside the IBM Series/1 minicomputer to which it was designed to be attached to. It featured a 66-key data entry style keyboard built into the terminal housing which had the same physical key arrangement as the 3277 data entry keyboard, but a different layout and keycap colour scheme.


The IBM 5100 Portable Computer was an early portable computer (at least portable by the standards of the time, weighing in at around 25kg) launched by IBM in 1975. The 5100 was designed to run either a BASIC interpreter, an APL one, or have the ability to toggle between them. The 75-key keyboard was available either with a standard layout, or an APL layout and featured the IBM Beamspring modules.


The IBM 5110 (launched 1978) was an updated version of the 5100 that supported additional peripherals. The keyboard and their layout were the same as those on the 5100 and on the 5120 but differed by the colour of their keycaps.


The IBM 5120 (launched 1980) was effectively the 5110 in a different form factor, with a larger screen and the tape drive replaced by a pair of 8" floppy drives. The keyboard and its layout was the same as those on the 5110.



The IBM Office was a word processor launched by IBM in 1977. Its keyboard has been described by some sources as being similar to that used by the later 5520 and DisplayWriter systems.


The System/32 was a midrange system, launched by IBM in 1975. It featured a console keyboard integrated into the computer unit, whose physical key layout could be described as a half way point between the layout of Selectric-based terminals such as the IBM 2741 and the keyboard of the IBM 5251 terminal which was designed for the later System/34.


The IBM System/38 Console was a midrange computer launched by IBM in 1979. In addition to the IBM 5250-series terminals that it was designed to operate with, it featured a console built into the computer unit whose keyboard had the same physical key arrangement as the 75-key 3278 keyboard.

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