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Micro Switch SD Series switches

This page documents known Micro Switch SD Series Hall effect keyboard switches (formerly known as “Honeywell Hall Effect” within the keyboard enthusiast community). Both the catalogue listing numbers and identification codes are given for convenience. Some types are taken from Honeywell charts, some from discovered keyboards, and the rest from surplus part listings. There are over a thousand possible types, but most such types are unlikely to have been produced.

Parts listed on supplier sites are almost always out of stock, overpriced (often extortionately so), or big boys’ club only. Outbound links are only offered to deserving suppliers where parts are stocked and made available at a reasonable price. The supplier names are given only as a reassurance that the data was present on another website; no guarantee is made that the part numbers are accurate and that the parts listed exist (the entries could have been mistyped).

The types with prefix letters (e.g. Q4A3B) are not shown with catalogue listing numbers, as no catalogue listing numbers have been confirmed for these types. (The prefix letter is not guaranteed to be part of the catalogue listing number.)

Abbreviated identification codes are listed first, to avoid confusion. Where switches have not been assumed, the identification code is an assumption only, as some types used abbeviated identification codes. 1001SD chart 7 shows abbreviated identification codes with a space before the “S”, while in practice this space has been found to be omitted. Catalogue listing numbers in italics are guesses based on abbreviated identification codes. The existence of A/B, S/T and V keystems that all look the same prevents precise identification.

A source of “⌨️” indicates that the switch is given on the SD keyboards page.

Cat. listing Ident. code Type Keycap mount Weight Output Source Observed NSN
1SD1C1A-R 1C1A Momentary NCR blade 1.3 oz Sink level eBay
(1001SD6B1D) 1DS Support Stepped 1.3 oz None ⌨️
(1001SD4B1A) 1AS
1A S
Momentary Square, stepped 1.3 oz Sink level ⌨️
1001SD1C1A Momentary NCR blade 1001SD chart 7
1001SD1C1B 1B S Momentary NCR blade 1.3 oz Sink pulse 1001SD chart 7
(1001SD4B3A) 3AS
3A S
Momentary Square, stepped 2.5 oz Sink level ⌨️
1001SD1C3A Momentary NCR blade 1001SD chart 7
1001SD2C3A Alternate action NCR blade
(1001SD12B3A) N3AS Illuminated Blade, stepped 2.5 oz Sink level ⌨️
(1001SD4B3B) 3BS
3B S
Momentary Square, stepped 2.5 oz Sink pulse ⌨️
1001SD1C3B Momentary NCR blade 1001SD chart 7
(1001SD4B6A) 6AS Momentary Square, stepped 6.0 oz Sink level ⌨️
1001SD1C6B 6B S Momentary NCR blade 6.0 oz Sink pulse 1001SD chart 7
1001SD1A3A 1A3A Momentary Square, sloped 2.5 oz Sink level Own collection
1001SD1A3B 1A3B Momentary Square, sloped 2.5 oz Sink pulse ⌨️
1001SD1A3S 1A3S Momentary Square, sloped 2.5 oz Logic scan ⌨️
1001SD1A8S 1A8S Momentary Square, sloped 8.0 oz Logic scan ⌨️
1001SD1B3A 1B3B Momentary Square, stepped 2.5 oz Sink level Own collection
1001SD1B3B 1B3B Momentary Square, stepped 2.5 oz Sink pulse ⌨️
1001SD1B3S 1B3S Momentary Square, stepped 2.5 oz Logic scan Deskthority
1001SD1F1A 1F1A Momentary Flat 1.3 oz Sink level Odyssey Electronics
1001SD1F3A 1F3A Momentary Flat 2.5 oz Sink level ISO Group 5930-01-090-1602
1001SD1F3K 1F3K Momentary Flat 2.5 oz Timed repeat Odyssey Electronics
1001SD1F3S 1F3S Momentary Flat 2.5 oz Logic scan ⌨️
1001SD1F5A 1F5A Momentary Flat 3.5 oz Sink level ⌨️
1001SD1K3S 1K3S Momentary Special blade 2.5 oz Logic scan Deskthority
D1K3S Momentary Special blade 2.5 oz Logic scan ⌨️
1001SD2A3A 2A3A Alternate action Square, sloped 2.5 oz Sink level Interdata [1]
1001SD2A6A 2A6A Alternate action Square, sloped 6.0 oz Sink level Interdata [1]
1001SD2A6S 2A6S Alternate action Square, sloped 6.0 oz Logic scan Oxygen Electronics
1001SD2K3S 2K3S Alternate action Special blade 2.5 oz Logic scan ⌨️
1001SD3B3S 3B3S Momentary Square, stepped 2.5 oz Logic scan Odyssey Electronics
1001SD4A1A 4A1A Momentary Square, sloped 1.3 oz Sink level ⌨️ 5930-01-167-7038
1001SD4A1B 4A1B Momentary Square, sloped 1.3 oz Sink pulse ⌨️
1001SD4A1D 4A1D Momentary Square, sloped 1.3 oz None Oxygen Electronics
1001SD4A1E 4A1E Momentary Square, sloped 1.3 oz Three-terminal ⌨️
1001SD4A1S 4A1S Momentary Square, sloped 1.3 oz Logic scan Odyssey Electronics
1001SD4A2B 4A2B Momentary Square, sloped 2.0 oz Sink pulse ⌨️
T4A2B Momentary Square, sloped 2.0 oz Sink pulse Deskthority
1001SD4A2K 4A2K Momentary Square, sloped 2.0 oz Timed repeat ⌨️
1001SD4A3A 4A3A Momentary Square, sloped 2.5 oz Sink level ⌨️ 5930-01-109-2286
Q4A3A Momentary Square, sloped 2.5 oz Sink level Own collection
1001SD4A3B 4A3B Momentary Square, sloped 2.5 oz Sink pulse Own collection
Q4A3B Momentary Square, sloped 2.5 oz Sink pulse Deskthority
1001SD4A3D 4A3D Momentary Square, sloped 2.5 oz None Odyssey Electronics
1001SD4A3E 4A3E Momentary Square, sloped 2.5 oz Three-terminal ⌨️
R4A3E Momentary Square, sloped 2.5 oz Three-terminal ⌨️
1001SD4A3S 4A3S Momentary Square, sloped 2.5 oz Logic scan ISO Group 5930-01-271-0012
U4A3S Momentary Square, sloped 2.5 oz Logic scan Deskthority
1001SD4A5A 4A5A Momentary Square, sloped 3.5 oz Sink level Odyssey Electronics
1001SD4A6A 4A6A Momentary Square, sloped 6.0 oz Sink level NSN 5930-01-110-9544
1001SD4A6B 4A6B Momentary Square, sloped 6.0 oz Sink pulse Quest Components
1001SD4A8E 4A8E Momentary Square, sloped 8.0 oz Three-terminal ⌨️
1001SD4B1D 4B1D Momentary Square, stepped 1.3 oz None ⌨️
1001SD4B1E 4B1E Momentary Square, stepped 1.3 oz Three-terminal ⌨️
1001SD4B1K 4B1K Momentary Square, stepped 1.3 oz Timed repeat ⌨️
1001SD4B1S 4B1S Momentary Square, stepped 1.3 oz Logic scan Deskthority
1001SD4B2K 4B2K Momentary Square, stepped 2.0 oz Timed repeat ⌨️
1001SD4B3A 4B3A Momentary Square, stepped 2.5 oz Sink level ⌨️
1001SD4B3B 4B3B Momentary Square, stepped 2.5 oz Sink pulse ⌨️
T4B3B Momentary Square, stepped 2.5 oz Sink pulse ⌨️
1001SD4B3E 4B3E Momentary Square, stepped 2.5 oz Three-terminal ⌨️
R4B3E Momentary Square, stepped 2.5 oz Three-terminal Deskthority
1001SD4B3K 4B3K Momentary Square, stepped 2.5 oz Timed repeat ⌨️
1001SD4B3S 4B3S Momentary Square, stepped 2.5 oz Logic scan ⌨️
1001SD4B6E 4B6E Momentary Square, stepped 6 oz Three-terminal ⌨️
1001SD4N1E 4N1E Momentary Flat, stepped with pompom 1.3 oz Three-terminal ⌨️
1001SD4S1B 4S1B Momentary Square, sloped 1.3 oz Sink pulse Odyssey Electronics
1001SD4T2B 4T2B Momentary Square, stepped 2.0 oz Sink pulse ⌨️
1001SD4T3S 4T3S Momentary Square, stepped 2.5 oz Logic scan Deskthority
1001SD4U3E 4U3E Momentary Cruciform 2.5 oz Three-terminal ⌨️
R4V3E Momentary Square, sloped 2.5 oz Three-terminal ⌨️
1001SD5A3E 5A3E Alternate action Square, sloped 2.5 oz Three-terminal ⌨️
1001SD5A6A 5A6A Alternate action Square, sloped 6 oz Sink level ⌨️
1001SD5B3A 5B3A Alternate action Square, stepped 2.5 oz Sink level ⌨️
1001SD5B3E 5B3E Alternate action Square, stepped 2.5 oz Three-terminal ⌨️
1001SD5B3S 5B3S Alternate action Square, stepped 2.5 oz Logic scan ⌨️
1001SD6A1D 6A1D Support Sloped 1.3 oz None ⌨️ 5930-01-167-7037
1001SD6B1D 6B1D Support Stepped 1.3 oz None ⌨️ 5930-01-295-7817
1001SD8A1A 8A1A Tactile Square, sloped 1.3 oz/70 gf Sink level Santa Clara Systems, Inc.
1001SD9A3A 9A3A Illuminated Blade, sloped 2.5 oz Sink level Interdata [1]
1001SD9B3B 9B3B Illuminated Blade, stepped 2.5 oz Sink pulse ⌨️
1001SD10B1A 10B1A Secretarial shift Square, stepped 1.3 oz Sink level ⌨️
1001SD10B3A 10B3A Secretarial shift Square, stepped 2.5 oz Sink level ⌨️
1001SD10B3S 10B3S Secretarial shift Square, stepped 2.5 oz Logic scan ⌨️
1001SD11A1A 11A1A Momentary tactile Square, sloped 1.3 oz/70 gf Sink level Soluparts
1001SD11B1A 11B1A Momentary tactile Square, stepped 1.3 oz/75 gf Sink level ⌨️
1001SD11B1S 11B1S Momentary tactile Square, stepped 1.3 oz/75 gf Logic scan ⌨️
1001SD11B2S 11B2S Momentary tactile Square, stepped 2.0 oz/95 gf Logic scan ⌨️
1001SD12A3A 12A3A Illuminated Blade, sloped 2.5 oz Sink level Odyssey Electronics
1001SD12B3A 12B3A Illuminated Blade, stepped 2.5 oz Sink level Quest Components
1001SD12B3S 12B3S Illuminated Blade, stepped 2.5 oz Logic scan Deskthority
1001SD16B2E 16B2E Momentary Slot, stepped 2.0 oz Three-terminal Deskthority
1001SD16B3E 16B3E Momentary Slot, stepped 2.5 oz Three-terminal ⌨️
  1. Interdata Master Part Number List (1/26/79) (note that the OCR data contains typos, e.g. “10015D9A3A”, “1001501A3A”, and that the document reports the alternate action switches as momentary)