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.

5251 & 5252

The IBM 5251 and 5252, part of the IBM 5250 Information Display System, were video terminals meant to be application configurable means of data entry, located away from, or directly attached to the host system. They could be attached to a variety of hosts, including: series /1, system/34 or system/38. IBM suggested using the terminals in areas such as a sales counter, an order entry department or a receiving department. The 5252 differed from the 5251 in that the 5252 shared a single display that was split with a mirror between two operators to create two screens, however both units shared the same keyboard offerings. They featured four different keyboards, a 83 key keyboard (standard), a 86 key keyboard (Katakana) a 66 key keyboard (data entry) and a 67 key keyboard (data entry with split spacebar). The 83 key keyboard shares its layout with the later Model F 83 key IBM System/23 Datamaster, IBM 5291 terminal and IBM PC keyboards as well as the 5280 Distributed Data Station keyboards discussed below. The 66 key variant dropped the number pad and featured "data entry" key legends, shown above. The 67 key layout was nearly identical to the 66 key layout, but had a split spacebar with a 3 unit zero key on the right side. The Katakana variant had 3 extra keys to accommodate the expanded character set. Legends were offered in several different languages, including German and Japanese, shown above. The 5250 system offered a light pen accessory which allowed the user to select highlight and copy text by dragging the light pen across the screen.

5253 & 5254

The IBM 5253 Display Station and the dual screen 5254 were video terminals made for the IBM 5520 Administrative System, and were amalgamations of the 5251/5252 and the later 6580 Displaywriter System. The terminals, which looked identical to the 5251/5252, supported 3270 emulation and were designed to create, process and manage documents locally or remotely. The keyboards which were almost identical to the 6580 Displaywriter, had two known layout options: an 82 key, 92 character keyboard (shown above) and an 84 key, 96 character keyboard. The major differences between the keyboards of the Displaywriter and the Administrative System were the color of the keys, and the legends, with the Displaywriter having white keys and the Administrative System having black keys and more specialized legends. Not very much is known about this system because it was it was a commercial failure and was withdrawn from marketing after only three and a half years.[7]

5281 & 5285

The 5281 and 5285 were video terminals made for the 5280 Distributed Data System. Described as a low cost way to enter data into and communicate data with larger computers, the 5280 offered increased performance from the 3740 Data Entry System which it was aiming to replace. Unique among IBM terminals, the 5285 was able to act as a controller and process data on the spot without being connected to a host device. The keyboard offerings were identical to the offerings for the 5250 System, however the bezels on the sides were shortened and the bottom bezel was elongated, to create a palm rest. As a result, the standard 83 key keyboard has the same form factor as the later Model F IBM 5291 terminal and Datamaster 5324 keyboards, and was the first keyboard to have this form factor. The top of the case is a cheaper and thinner plastic than on most beamsprings, and also yellows with age and light exposure, unlike most other models. While the legends are mostly identical to those from the 5250 System, there are a handful of unique legends on the number pad and function cluster. These keyboards use a speaker for auditory feedback similar to the 6580 Displaywriter and 4978 Display Station keyboards. Bizarrely, the speaker location was changed midway through production and was moved from being mounted in the upper right to the bottom left on later keyboards.


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


Contrary to popular belief, the 1130 was created and sold years before the beamspring patent was filed, and does not have beamspring switches, however the keycaps are interchangeable.


Contrary to popular belief, the 2260 was created and sold years before the beamspring patent was filed, and does not have beamspring switches, however the keycaps are interchangeable.


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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