Micro Switch NW Series
Contents
Overview
Micro Switch NW is a series of keypads (at the time, referred to as “keyboards”), designed with low cost and low profile in mind. In a 1971 advertisement they were stated to be under 1 inch tall and tested to one million cycles. 12-key 3×4 and 16-key 4×4 layouts were offered, and 1×4 has also been encountered. Output could be either encoded or unencoded. NW keypads use “slow make, slow break contact action” which presumably means that contact closure distance is proportional to travel, as opposed to snap-action switches that instantaneously flip between released and pressed.
NW keypads as advertised used squircular spherical island keycaps. However, model 4NW6-1 has tall protruding plungers that appear to accept standard Micro Switch SW Series keycaps; no examples have been found with keycaps fitted.
The concept model for 12NW2-1 has circular spherical island keycaps that are not known from any other examples. This unit has one terminal per switch, and a second terminal against each switch in the two outer columns. The reasoning behind this is not known, as one would assume that either every switch would be fully isolated (as is generally the case in prefabricated arrays) or that all switches would share a single common terminal. However, the primary arrangement according to the 1971 advertisement was BCD or Excess 3 codes as well as unencoded, so it’s not entirely clear what output this keypad provided.
Examples
| Catalogue listing | Keycap style | Layout | Notes | Reference |
|---|---|---|---|---|
| 4NW3-1 | Island squircular spherical | 1×4 | TEDSS | |
| 4NW6-1 | External | 1×4 | No keycaps present | TEDSS |
| 12NW2-1 | Island circular spherical | 3×4 | Labelled “CONCEPT MODEL”; no date | Imgur |
Documentation
The following material was scanned by Bitsavers unless otherwise noted:
- NW keypads advertisement, Electronic Design, Vol. 19 No. 12, June 10 1971