Fujitsu FKB2500 Series
Fujitsu FKB2500 Series is a third-generation leaf spring standard and custom mechanical keyboard series. It was available in both “non-snap” linear and “snap” clicky versions. It is designed to be DIN-compliant. Fujitsu reported that these keyboards use FES-301E switches, where “E” denotes “ergonomic” (DIN-compliant).
The characteristics are curious. The bounce time at 10 ms is twice the typical bounce time of mechanical switches, but the 50 million cycle lifetime is substantially in excess of most mechanical switches of the time. The target operating force is approximately 50 cN. The tactile drop is depicted as around 5 cN.
The specifications below cover the individual switch units. The data below is taken from the datasheet.
|Total travel||3.8±0.5 mm|
|Operating force||49±24 cN|
|Lifetime||50 million times|
|Contact resistance||1 Ω or less at 6 V DC, 10 mA|
|Bounce time||10 ms or less|
- Fujitsu Micro 16 keyboard (N860-2505-T00201A)
- FKB2500 Series datasheet (fujitsu.com; 2001-10-03, modified 2004-07-22)