IBM Elastic Diaphragm encoded keyboards

IBM's third generation of keyboards

Contents

Background

IBM's Elastic Diaphragm encoded keyboards were their brief third generation of keyboards introduced in 1969 seemingly as an alternative for their previous Card Punch and typewriter-based keyboards. IBM Elastic Diaphragm keyboards were essentially an intermediate between IBM's practice of reusing said keypunch and typewriter products to serve as keyboards for systems unrelated to both keypunching and typewriting, and discrete self-contained switches as we know them today. They can be considered IBM's first family of keyboards that uses a named switch design, which in its most common form takes an IBM Selectric keyboard element and attaches a form of membrane sensor to the typebars. But they were quickly supplanted then and in popular discussion today by the IBM Model B family introduced just two years later. Keyboards of this era are generally recognisable for their wedge-shaped appearance.

Keyboards

5475 Data Entry Keyboard Attachment (1969)

The IBM 5475 Data Entry Keyboard is a 64-character keyboard similar to the IBM 5496 keyboard shown below. In fact, the keyboard was designed to look and operate much like the 5496 by design albeit with the addition of its own toggle switch based control panel^[5][5]
IBM - IBM System/3 Model 10 Components Reference Manual (#GA21-9103-5) [accessed 2022-09-03].. It was used for online keypunching and verifying^[6][6]
IBM - IBM System/3 field engineering announcement [accessed 2022-09-03].. It was available with the first IBM System/3s at launch, thus was likewise introduced in July 1969^[7][7]
IBM - IBM System/3 [accessed 2022-09-04].. Today, the IBM 5475 is considered the most well-known Elastic Diaphragm keyboard likely due to it being the titular keyboard in IBM's documentation of the switch itself^[8][8]
IBM - IBM Elastic Diaphragm Encoded Keyboards and 5475 Data Entry Keyboard Theory-Maintenance Manual (#SY27-0073-1) [accessed 2022-09-04]..

5496 Data Recorder Keyboard (1969)

The IBM 5496 Data Recorder was introduced alongside the 5475 shown above and the IBM System/3 at large in July 1969^[7][7]
IBM - IBM System/3 [accessed 2022-09-04]. and sports a 64-character keyboard that the aforementioned 5475 was designed to emulate. The Data Recorder at large was an offline component and was used to provide punched and printed source documents for a host System/3^[6][6]
IBM - IBM System/3 field engineering announcement [accessed 2022-09-03].. Since the Data Recorder unit itself has various control options, the 5496 notably lacked the toggle switches its 5475 siblings had.

2772 Multi-Purpose Control Unit Keyboard (1969)

The IBM 2772 Multi-Purpose Control Unit Keyboard was the keyboard used with the IBM 2770 Data Communication System. Its first appearance in IBM literature was in August 1969. The 2772 Multi-Purpose Control Unit itself was the controller for a 2770 system and could feature an IBM 2265 Display Station or printer to go with the keyboard^[9][9]
IBM - IBM Systems Reference Library System Components IBM 2770 Data Communication System (#A27-3013-0) [accessed 2022-09-03].. This keyboard was used for data entry and controlling the system. Its use of Elastic Diaphragm key-switches can be inferred from a graphic in IBM's literature on the switch which appears to show a variant of this very keyboard^[8][8]
IBM - IBM Elastic Diaphragm Encoded Keyboards and 5475 Data Entry Keyboard Theory-Maintenance Manual (#SY27-0073-1) [accessed 2022-09-04]..

5404/5406 System/3 Operator Keyboard Console (1970)

The IBM System/3 Operator Keyboard Console was largest keyboard available for any IBM System/3 model or configuration. It first appeared with the IBM 5406 (System/3 Model 6) that launched in 1970 and later 5404 (System/3 Model 4) from 1976^[10][10]
Wikipedia - IBM System/3#History [accessed 2022-09-03].^[11][11]
Norsk Teknisk Museum - File:IBM System3 model 4 (cropped).jpg [accessed 2022-09-03].. The keyboard was used for entering data into storage, controlling system functions via a bank of toggle switches, and controlling certain program operations and printer operations via 16 command keys^[12][12]
IBM - IBM System/3 Model 6 Introduction (#GA21-9122-1) [accessed 2022-09-03].. Various status lights were integrated for the system and command keys with the command key light covers being relegendable to indicate what function a command key provided. The IBM 5406 Processing Unit Parts Catalog indicates this keyboard uses Elastic Diaphragm key-switches and gives the part number 5151918 for an individual diaphragm^[13][13]
IBM - IBM 5406 Processing Unit Parts Catalog (#S134-0001-2) [accessed 2022-09-03]..

3672 Executive Console (1971)

The IBM 3672 Executive Console was the large 178-key keyboard component of the IBM 3670 Brokerage Communications System, a system developed by IBM Raleigh and and rolled out by IBM Data Processing Division in September 1971^[15][15]
IBM - DPD chronology [accessed 2022-09-03].. Then IBM Systems Development Division engineer Dennis Kekas worked on the keyboard design and confirmed it uses Elastic Diaphragm key-switches^[14][14]
JP! - IBM 178-key 3670 communications system keyboard [accessed 2022-09-03]. License/note: used under fair dealing..

Uncertain

System/360 Model 85 Operator Console Keyboard

http://www.bitsavers.org/pdf/ibm/360/model85/C27-6943-0_IBM_System360_Introduction_to_Model_85_Programmming_Support_196901.pdf (Page 15)

3066 Model 1 System Console Keyboard

https://www.itworldcanada.com/blog/changing-of-the-it-guard/92523

https://www.ibm.com/ibm/history/exhibits/mainframe/mainframe_2423PH3165.html

https://www.cl.cam.ac.uk/events/EDSAC99/e99_photos.html

3066 Model 2 System Console Keyboard

https://en.wikipedia.org/wiki/IBM_System/370_Model_168

http://bitsavers.trailing-edge.com/pdf/ibm/370/systemGuide/GC20-1755-2_370-168_Guide_Jun75.pdf

https://www.researchgate.net/figure/An-IBM-System-370-Model-168-In-this-photo-we-see-a-model-in-operation-at-CERN-in_fig1_364582088

https://blogs.ncl.ac.uk/cs-history/2019/09/08/a-moment-in-time-the-370-arrives/

http://history.cs.ncl.ac.uk/anniversaries/40th/images/ibm370_1682/print38.html

Sources

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