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 (1969)

The IBM System/3 was a midrange computer introduced in 1969 as a low-cost alternative for IBM mainframes such as the System/360 and was aimed at small organisations. It was targeted at such organisations that still used the IBM 1400 Data Processing Systems and Card Punch equipment. It was the beginning of the IBM midrange line that would eventually include famous computers such as IBM System/34, IBM AS/400 and current IBM i-based systems^[6][6]
Wikipedia - IBM System/3 [accessed 2023-12-12]..

The IBM 5475 Data Entry Keyboard was one of the two main keyboard options for the IBM System/3 Model 10 (5410 Processing Unit), the launch model introduced in July 1969^[7][7]
IBM - IBM System/3 [accessed 2022-09-04].. The other keyboard was the IBM 5471 Printer-Keyboard, a Selectric typewriter-based printer-keyboard. The 5471 was capable of performing more functions (including inquiries, data entry, operator/system communication, secondary printing, online data recording and online data verification) but required specific storage sizes and possible IBM servicing concerns. The 5475 had more limited functionality (data entry, online data recording and online data verification) but was more similar in layout and familiarity with the also 64-character IBM 5496 Data Recorder Keyboard (another possible IBM System/3 component)^[8][8]
IBM - IBM System/3 Model 10 Configurator (#GA21-9135-1) [accessed 2023-12-12]. License/note: document archived by bitsavers..

The 5475 keyboard is comprised of the keyboard assembly itself and a control panel. The control panel features 6 toggle switches - from left to right; Auto Skip/Duplicate, Auto Record Release, Program, Program Load, Print and Record Erase - which are all two-position switches except for the Record Erase Switch (which is a momentary switch). Several indicators are also included for indicating columns (via two 7-segment number displays), error and program card level^[5][5]
IBM - IBM System/3 Model 10 Components Reference Manual (#GA21-9103-3) [accessed 2023-12-12]. License/note: document archived by bitsavers, diagrams used under fair dealing.. The 5475 would connect to its host System/3 Processing Unit via the IBM 5475 Data Entry Keyboard Attachment (feature code 4120)^[8][8]
IBM - IBM System/3 Model 10 Configurator (#GA21-9135-1) [accessed 2023-12-12]. License/note: document archived by bitsavers.. Today, the 5475 is considered the most well-known Elastic Diaphragm keyboard likely due to it being the titular keyboard in IBM's documentation of the key-switch itself^[9][9]
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 System/3 was a midrange computer introduced in 1969 as a low-cost alternative for IBM mainframes such as the System/360 and was aimed at small organisations. It was targeted at such organisations that still used the IBM 1400 Data Processing Systems and Card Punch equipment. It was the beginning of the IBM midrange line that would eventually include famous computers such as IBM System/34, IBM AS/400 and current IBM i-based systems^[6][6]
Wikipedia - IBM System/3 [accessed 2023-12-12]..

The IBM 5496 Data Recorder was an offline component for System/3 used to provide punched and printed source documents for a host System/3^[10][10]
IBM - IBM System/3 field engineering announcement [accessed 2022-09-03].. The IBM 5496 Data Recorder Keyboard itself has layout similarity with the also 64-character IBM 5475 Data Entry Keyboard (another possible IBM System/3 component). 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^[11][11]
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^[9][9]
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^[12][12]
Wikipedia - IBM System/3#History [accessed 2022-09-03].^[13][13]
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^[14][14]
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^[15][15]
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^[17][17]
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^[16][16]
JP! - IBM 178-key 3670 communications system keyboard [accessed 2022-09-03]. License/note: used under fair dealing..

Sources

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