Editing Micro Switch SD Series

{{TODO rethink|reason=the content relating to SW and SN series needs moving to the respective pages; also, this page is chaotic; also, use of a regular expression for model numbering is pretty brutal (now we have two problems ......)}}
{{TODO photo|more=true|reason=family portrait for infobox; dedicated variants table images}}
{{TODO verify|details=known variants list is almost entirely redlinks!}}

{{Infobox dswitch
| image name        = Telex-270-4B1E-Switch-Alone.jpg
| manufacturer      = [[Micro Switch]]
| inventor          = Everett A. Vorthmann<br/>Joeseph T. Maupin
| switch type       = [[Switch terminology#Linear Switch|Linear]], [[Switch terminology#Linear Switch|Tactile]]
| contact mechanism = [[Contact mechanism#Hall effect|Hall effect]]
| product code      = 
| lifetime          = Tested up to 30 billion<br/>(extremely long)
| peak force        = 45 g to 320 g{{citation needed}}
| supersedes        = [[Micro Switch SW Series]]
}}

==History==
Honeywell Hall Effect switches are advertised and tested to be a switch with an incredibly long lifetime, and designed with reliability in mind. There are both three and four pin designs of the switch, depending on the type of sensor. The four pin sensors are +5, GND and dual open-collector outputs, allowing wired-or of the X, Y keyboard matrix. The switches are naturally bounce free due to the sensing method.

The Honeywell Hall Effect switch is well-known for it's use on some [[Symbolics]] keyboards, as well as the [[Space-cadet keyboard]].

The last accessible reference to SN and SD series on the Honeywell website is from the 22nd of February 1999.<ref name="IAWM-SD-SN" /> The products list at this time were:

*'''Hall-Effect Keyboards''' Sales Sheet (02509_a.pdf)
*'''SD16 Keyswitch Modules''' Product Sheet (02503_0.pdf)
*'''63SD30-4 Microcomputer-based Keyboard''' Product Sheet (02504_0.pdf)
*'''26SD1-2 Point-of-Sale Keyboard''' Product Sheet (02506_0.pdf)
*'''12SD/16SD Numeric Keyboards''' Product Sheet (02607_0.pdf)

The PDF documents were not archived. Later that year, Honeywell redesigned their website such that it could no longer be crawled (product data was accessible through form submission), so it is not clear when SD and SN series were phased out.

==Features (as per [[Honeywell]])==
Details for switch Model 4A3A which should be consistent across all models, except for operating force:

*'''Total Travel''' - 0.160 in (4.1 mm) nom.
*'''Force''' at operating point - 2.8 oz. (78 g) nom.
*'''Pretravel''' - 0.090 in. (2.3 mm) nom.
*'''Release point''' at 5 VDC and 75°F (24°C) (With respect to free position) - 0.040 in. (1.0 mm) min.

Note that according to the 1998 1001SD Series Chart 2 (listed within Micro Switch SD16 Keyswitch Modules, below) this should be 0.695 N/2.5 oz, so the specifications may have changed over time.

===Part Numbers===
Micro Switch and Honeywell switches typically have the series name within the part number, which was apparently notably not the case for SD Series. According to the 1998 1001SD Series Chart 2, the part numbers are of the form 1001SDnnnn, where the four-character "identification code" is all that is printed on the switch, for brevity.

As a regular expression, the models can be shown as shown below. Descriptions given in italics are observations not corroborated with Micro Switch documentation.

According to the datasheet, "sloped" switches have upright stems: the description refers to how a tilted keyboard the keycap top surfaces will be sloped. Angled stem switches are called "stepped" due to the presentation of a staircase profile in a tilted keyboard.

([A-Z])?([0-9]+)([A-Z])([0-9])([A-Z])

#([A-Z])? '''Sensor variant?''' (All sensor PCBs with this code have this printed on it)
#*D - ?
#*Q - ?
#*R - ?
#*T - ?
#([0-9]+) '''Switch variant'''
#*1 - ''Unknown (white stem)''
#*4 - Momentary action (black stem)
#*5 - Alternate action (black stem)
#*6 - Support (short black stem)
#*10 - External latching, used on both caps lock and shift on some keyboards.
#*11 - ''Black stem, tactile''
#*12 - ''LED keycap stem''
#*16 - ''Alternate keyboard mount''<ref name="MouseFan_altmicro" />
#([A-Z]) '''Stem type'''
#*A - Sloped ''(non-angled)''
#*B - Stepped ''(angled)''
#*F - ''No keycap stem''
#*G - Flat top
#*H - Flat-stepped
#*K - ''Narrow bar stem''
#*S - Sloped
#*T - Stepped ''(ridged housing)''
#([0-9]) '''Switch weighting''' (hard to read in the datasheet; some figures are best guesses)
#*1 - 0.362 N/1.1 oz
#*2 - 0.556 N/2.0 oz
#*3 - 0.695 N/2.5 oz
#*5 - 0.973 N/3.5 oz
#*6 - 1.668 N/6.0 oz
#*8 - 2.224 N/8.0 oz
#*4 - No spring (use with three unit button)
#([A-Z]) '''Switch output'''
#*A - Sink level ''(4 pins, 2 redundant sense lines)''
#*B - Sink pulse
#*C - Source level
#*E - ''3 pins, 1 sense line''
#*K - Timed repeat ''(4 pins, 2 redundant sense lines)''
#*S - Logic scan ''(4 pins: +5, OUT, IN, GND)''
#*D - None

===Known Variants===
Variants are listed in order of part number. The extra character found at the start of some part numbers is treated separately for the purposes of sorting; for example D1K3S is listed after 1K3S.

{| class="wikitable variants-table"
!
!Number
!Action
!Keystem
!Weight
!Signal
!Known usage
|-
|[[Image:Micro Switch-SD-1A3A.jpg|100x100px|none]]
|1A3A
|Momentary
|Square, sloped
|2.5 oz
|Sink level
|[[Micro Switch 68SD15-1-E]]
|-
|[[Image:Micro-Switch-SD-1A3B.JPG|100x100px|none]]
|1A3B
|Momentary
|Square, sloped
|2.5 oz
|Sink pulse
|[[Micro Switch 68SD15-1-E]]
|-
|[[Image:TI-Silent-700-745-Switch-1A3S.JPG|100x100px|none]]
|1A3S
|Momentary
|Square, sloped
|2.5 oz
|Logic scan
|[[TI Telex 58SD17-2-B]], [[TI Silent 700 Model 745|TI Silent 700 Model 745 (63D17-3-B)]]
|-
| |[[Image:TI-Silent-700-745-Switch-1A8S.JPG|100x100px|none]]
|1A8S
|Momentary
|Square, sloped
|8.0 oz
|Logic scan
|[[TI Telex 58SD17-2-B]], [[TI Silent 700 Model 745|TI Silent 700 Model 745 (63SD17-3-B)]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|1B3S
|Momentary
|Square, stepped
|2.5 oz
|Logic scan
|[[Nokia MikroMikko 1 keyboard]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|1F5A
|Momentary
|None
|3.5 oz
|Sink level
|[[UGC-74 Keyboard]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|1K3S
|Momentary
|Bar
|2.5 oz
|Logic scan
|[[Bunker Ramo ADMIN 20211322]]
|-
|[[Image:D1K3S Honeywell Hall Effect.jpg|100x100px|none]]
|D1K3S
|Momentary
|Bar
|2.5 oz
|Logic scan
|[[Bunker Ramo ADMIN 20403025]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|2K3S
|Momentary
|Bar
|2.5 oz
|Logic scan
|[[Bunker Ramo ADMIN 20403025]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|4A1A
|Momentary
|Square, sloped
|1.1 oz
|Sink level
|[[Honeywell 26SD1-2-H]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|4A1E
|Momentary
|Square, sloped
|1.1 oz
|?
|[[Burroughs TP110]], [[Burroughs TP130]], [[Burroughs RIII]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|T4A2B
|Momentary
|Square, sloped
|2.0 oz
|Sink pulse
|[[Wang 271-1126]] (Meaning of T is unknown)
|-
|[[Image:No photograph.svg|100x100px|none]]
|4A2K
|Momentary
|Square, sloped
|2.0 oz
|Timed repeat
|[[Wang 271-1126]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|4A3A
|Momentary
|Square, sloped
|2.5 oz
|Sink level
|[[Bud Keypad 83959]], [[Honeywell 26SD1-2-H]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|Q4A3B
|Momentary
|Square, sloped
|2.5 oz
|Sink pulse
|[[Wang 271-1126]] (Meaning of Q is unknown)
|-
|[[Image:No photograph.svg|100x100px|none]]
|4A3E
|Momentary
|Square, sloped
|2.5 oz
|?
|[[Burroughs TP110]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|R4A3E
|Momentary
|Square, sloped
|2.5 oz
|?
|[[Burroughs TP130]] (Meaning of the R is unknown)
|-
|[[Image:No photograph.svg|100x100px|none]]
|4A8E
|Momentary
|Square, sloped
|8.0 oz
|?
|[[Burroughs TP110]], [[Burroughs TP130]]
|-
|[[Image:Telex-270-4B1D-Switch-Alone.jpg|100x100px|none]]
|4B1D
|Momentary
|Square, stepped
|1.1 oz
|None
|[[Convergent 64-00164]], [[Telex 270 Keyboards#PN: 952003-222|Telex 278]]
|-
|[[Image:Telex-270-4B1E-Switch-Alone.jpg|100x100px|none]]
|4B1E
|Momentary
|Square, stepped
|1.1 oz
|?
|[[Space-cadet keyboard|Space-cadet]], [[Telex 270 Keyboards#PN: 952003-222|Telex 278]], [[Burroughs RIII]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|4B1S
|Momentary
|Square, stepped
|1.1 oz
|Logic scan
|[[Convergent 64-00164]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|4B2E
|Momentary
|Square, stepped
|1.1 oz
|?
|[[Burroughs RIII]]
|-
|[[Image:Telex-270-4B3E-Switch-Alone.jpg|100x100px|none]]
|4B3E
|Momentary
|Square, stepped
|2.5 oz
|?
|[[Symbolics 3600 Rev D]], [[Space-cadet keyboard|Space-cadet]], [[Telex 270 Keyboards#PN: 952003-222|Telex 278]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|4B3K
|Momentary
|Square, stepped
|2.5 oz
|Timed repeat
|[[Wang 271-1126]]
|-
|[[File:4B3S.jpg|100x100px|thumb|none|4B3S]]
|4B3S
|Momentary
|Square, stepped
|2.5 oz
|Logic scan
|[[Intergraph 2710]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|4T3S
|Momentary
|Stepped
|2.5 oz
|Logic scan
|[[Convergent 64-00164]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|5A3E
|Alternate
|Square, sloped
|2.5 oz
|?
|[[Burroughs TP110]], [[Burroughs TP130]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|6A1D
|Support
|Square, sloped
|1.1 oz
|None
|[[Convergent 64-00164]], [[Burroughs TP110]], [[Burroughs TP130]], [[Burroughs RIII]]
|-
|[[Image:Telex-270-6B1D-Switch-Alone.jpg|100x100px|none]]
|6B1D
|Support
|Square, stepped
|1.1 oz
|None
|[[Convergent 64-00164]], [[Space-cadet keyboard|Space-cadet]], [[Honeywell 26SD1-2-H]], [[Telex 270 Keyboards#PN: 952003-222|Telex 278]], [[Burroughs RIII]]
|-
|[[File:9B3B.jpg|left|thumb|106x106px]]
|9B3B
|Momentary
|LED support
|?
|?
|[https://deskthority.net/viewtopic.php?f=62&t=23087 SD-16073]
|-
|[[Image:Micro-Switch-SD-12B3S.jpg|100x100px|none]]
|12B3S
|Momentary
|LED support
|2.5 oz
|?
|[[Convergent 64-00164]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|10B2E
|Momentary
|Square, stepped
|2.2 oz
|?
|[[Burroughs RIII]]
|-
|[[Image:No photograph.svg|100x100px|none]]
|16B3E
|Momentary
|Alternate, stepped
|2.5 oz
|?
|[[Sun 32SD38-4-E]]
|}

==Availability==
SD Series appear to have gone out of production circa 1999 or 2000. Keyboards with the switches occasionally appear on auction sites such as Ebay, but it is not always obvious. Nearly all keyboards using Microswitch SD require a [[Converter|converter]]. The last known keyboard with these switches was made in mid 1996 for [[Sun Microsystems]]. Further research has shown that Honeywell has been using their "dual magnet" design to make backlit switches for industrial keyboards as recently as 1999.{{citation needed}}

==Electrical Characteristics==
[[File:Honeywell_HallEffect_SwitchCircuitDiagram.png|400px|Sense circuit schematic for a Honeywell Hall Effect switch]]
[[File:Honeywell_HallEffect_CurrentSinking.png|500px|Sense circuit current sinking profile]]

==Controller Sensing Characteristics==
[[File:Honeywell_HallEffect_ControllerScanCircuit.png|350px|Sense circuit schematic for a Honeywell Hall Effect switch]]
[[File:Honeywell_HallEffect_ControllerScanCharacteristics.png|500px|Sense circuit current sinking profile]]

==Switch Dimensions==
[[File:Honeywell_HallEffect_16SD3-5_Schematic.png|500px|16SD3-5 Hall Effect Keypad schematic, top view]]
[[File:Honeywell_HallEffect_16SD3-5_Schematic3.png|350px|16SD3-5 Hall Effect Keypad schematic, side view, keytops]]
[[File:Honeywell_HallEffect_16SD3-5_Schematic2.png|300px|16SD3-5 Hall Effect Keypad schematic, side view, no keytops]]

==Documentation==
*[[:File:Micro Switch SN+SD series.pdf|Micro Switch SN/SD Series]]
*[[:File:Micro Switch SD16 Keyswitch Modules.pdf|Micro Switch SD16 Keyswitch Modules]] (with 1001SD Series Chart 2)

==Keyboards==
*Burroughs TP110<ref name="TP110"/>
*Burroughs TP130<ref name="TP130"/>
*Burroughs RIII<ref name="burroughs"/>
*Convergent Technologies CT 64-00164<ref name="Convergent"/>
*Datagraphix 132B<ref name="data"/>
*Micro Switch SD-16255<ref name="SD16255"/>
*Nokia MikroMikko 1<ref name="Nokia"/>
*[[Pertec XL40 keyboard]]
*Selenia Tina 270 78<ref name="selenia"/>
*[[Space-cadet keyboard]]
*Some [[Symbolics 364000]]
*[[Telex 270 Keyboards|Telex 270 keyboards]]
*[[TI Silent 700 Model 745|Texas Instruments TI Silent 700 Model 745]]
*UGC-74<ref name="UGC"/>
*Wang 271-1126<ref name="Wang"/>

==Typewriters==
*Honeywell 70SD22-4 typewriter module (Tactile)<ref name="tactile"/>

==Keypads==
*Bud 83959<ref name="Bud"/>
*Sun 32SD38-4-E<ref name="Sun"/>

==External Links==
*dork_vader_exe — [https://www.flickr.com/photos/dork_vader/sets/72157662093794783 Hall Effect Switch Compendium switches] Retrieved 2016-02-14.
*dork_vader_exe — [https://www.flickr.com/photos/dork_vader/sets/72157662083935704 Hall Effect Switch Compendium keycaps] Retrieved 2016-02-14.
*Google — [https://docs.google.com/open?id=0B4Wyz4bY7XjLNTdiMjFkNjEtMWI1Yi00YWQ3LTk3ZDctMzkxOTAzY2VjOTdj Honeywell Keypad Datasheet] Retrieved 2015-07-27.
*MouseFan — [http://mousefan.telcontar.net/image/micro.htm SUN 32SD38-4-E USA] — Last known manufactured Honeywell Hall Effect switch (Japanese only). Last updated 2004-05-02. Retrieved 2015-07-27.
*Honeywell.com — [http://sensing.honeywell.com/index.php?ci_id=47847 Technical document on Honeywell Hall Effect switches] Retrieved 2015-07-27.

==References==
<references>
<ref name="MouseFan_altmicro">MouseFan — [http://mousefan.telcontar.net/image/micro.htm SUN 32SD38-4-E USA] (Japanese only) Last updated 2004-05-02. Retrieved 2018-01-23.</ref>
<ref name="IAWM-SD-SN">(Wayback Machine) Honeywell.com — [http://web.archive.org/web/19990222151529/http://www.honeywell.com/sensing/prodinfo/halleffect/ Hall-Effect Keyboards] Archived 1999-02-22.</ref>
<ref name="Convergent">Deskthority — [https://deskthority.net/viewtopic.php?t=24969 Convergent Technologies CT 64-00164 Micro Switch Vintage Keyboard Serial Output] Posted 2020-12-10.</ref>
<ref name="TP130">Deskthority — [https://deskthority.net/viewtopic.php?t=3664 Burroughs TP130] Posted 2012-08-09.</ref>
<ref name="Wang">Imgur — [https://imgur.com/a/84caj wang keyboard] Uploaded 2015-11-07.</ref>
<ref name="TP110">Deskthority — [https://deskthority.net/viewtopic.php?t=18872 Burroughs TP110 keyboard] Posted 2018-05-01.</ref>
<ref name="UGC">Deskthority — [https://deskthority.net/viewtopic.php?t=8749 UGC-74 Keyboard] Posted 2014-09-13.</ref>
<ref name="Sun">Mousefan — [https://mousefan.telcontar.net/image/micro.htm Sun 32SD38-4-E USA 1996] Accessed 2022-04-10.</ref>
<ref name="Bud">Geekhack — [https://geekhack.org/index.php?topic=18048.0 Bud/Honeywell Hall Effect Keypads (~30)] Posted 2011-05-13.</ref>
<ref name="Nokia">Imgur — [https://imgur.com/a/7u23V Nokia MikroMikko 1 keyboard] Uploaded 2013-11-29.</ref>
<ref name="data">YouTube — [https://www.youtube.com/watch?v=VEOWbsMyaF8&ab_channel=mcmaxmcmc Datagraphix 132B Keyboard Typing Demo] Uploaded 2022-06-28.</ref>
<ref name="tactile">Deskthority — [https://deskthority.net/viewtopic.php?f=62&t=27366&p=505492 Tactile Micro Switch SD typewriter module w/ secretarial shift 70SD22-4] Posted 2022-07-07.</ref>
<ref name="SD16255">Imgur — [https://imgur.com/a/RuTWCIS Micro Switch SDR SD-16255 EIA349-1-0] Uploaded 2022-08-06.</ref>
<ref name="selenia">Deskthority — [https://deskthority.net/viewtopic.php?t=23089 SELENIA TINA 270 78 Key] Posted 2019-11-27.</ref>
<ref name="burroughs">Deskthority - [https://deskthority.net/viewtopic.php?f=2&t=27805 NOS Micro Switch SD Keyboard - 1981 - Burroughs RIII Keyboard] Posted 2022-12-06.</ref>
</references>

[[Category:Hall effect switches]]
[[Category:Honeywell switches]]
[[Category:DPST switches]]
[[Category:Linear switches]]
[[Category:Micro Switch switches]]
[[Category:Keyboard switches with a square post mount]]
[[Category:List of all keyboard switches]]