|Headquarters||Freeport, Illinios, USA|
Micro Switch of Freeport, Illinois is a division of Honeywell. Micro Switch existed as a division of the First Industrial Corporation before 1950 when it was purchased by Honeywell.
Micro Switch keyboard and keyboard switch part numbers ("catalog listing" numbers) generally contain the two-letter series name in the middle. For keyboards, the digits to the left of the series name give the number of keys on a keyboard. For example, the 66-key IBM 3277 typewriter keyboard (part of SW Series) has catalogue listing number 66SW6-4, while the SC Series 92-key ITT Courier 1700 has catalogue listing number 92SC40-23. To the right of the series name are characters that give the keyboard design a unique identity.
For switches, the digits before the series name vary by series. For SW Series, the digit 1 is used, presumably on the basis that there are no one-key keyboards; an example is 1SW12-BL, a switch found in the IBM 3277 typewriter keyboard. For SD Series, the number 1001 is used instead, but these digits and the series name are both omitted from the switch; for example, switch type 1001SD4B3E is labelled simply "4B3E" in the space available. SN Series uses 101SN* and 201SN*, which suggests that these were never used in full-size keyboards.
Micro Switch's first Hall effect solid-state switch was introduced in 1965. This was followed by what they claimed was the world's first solid-state keyboard, in 1968. This is likely to be Micro Switch SW Series.
The most commonly-occurring switch series is "Honeywell Hall Effect", Micro Switch SD Series. SD Series itself covers both the keyboards and the switches it used. Micro Switch produced other ranges of Hall effect switches as well as reed keyboard switches.
Some keycaps have some odd properties such as this Caps Lock LED keycap (Switch Model 12B3S). Honeywell Hall Effect keycaps are known to be exclusively double-shot, using very thick plastic in all cases. While the switch isn't in production anymore, there were many variants of the switch, with a specific naming scheme to the models.In almost all standard variants of the switch, there is a spot for a LED add-on part as seen in the Convergent 64-00164 keyboard.
SD Series keycaps
- Honeywell — Celebrating 75 years of MICRO SWITCH Retrieved 2015-12-12.
- Internet Archive Wayback Machine — History (archived 1999-04-22)