Editing Micro Switch SD Series (section)

==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.