NMB desktop membrane keyboards
NMB are notable for a widely-used style of membrane switch using a proprietary-mount plunger over rubber dome. In time, the use of a separate plunger was phased out. Production of desktop membrane keyboards ended in 2015 when NMB left the keyboard market.
Travel for the membrane types is given as 0.140±0.020″ (3.56±0.5 mm), which is exactly the same as the figure given for the Series 725 mechanical series RT-8200W.
|Model||Lifetime (Feb. 1997)||Lifetime (Feb. 1999)|
|RT-6600W||20 million||20 million|
|RT-6800W||20 million||20 million|
|RT-9100W||20 million||20 million|
The general specifications are the same across all models, although rated lifetime varies by model:
|Full travel||0.140±0.020″ (3.56±0.5 mm)|
|Pretravel||0.090±0.020″ (2.29±0.5 mm)|
|Operating force||2.0 oz nominal (55 gf)|
|Rated lifetime||20 million cycles||10 million cycles|
|Legend printing||Unspecified||Laser etched||Laser marked|
|Switch type||With discrete plunger||Not depicted|
|Contact material||Unspecified||Mylar with silver–carbon overlay|
The documents are mostly marked with a code such as “KB10/98”, which is taken to be the month and year that it was written. The PDFs themselves were archived by the Wayback Machine in later years.