Unseen switches
A surprising amount of switch types are known from literature, but have never been seen, or have never been discovered in a keyboard.
Contents
Never seen
The following switch types are known from patents or catalogues, but have never been observed or depicted in a photograph:
- Alps SKFR/SKFS LED models (SKFRFA, SKFRFB, SKFRFC)
- Bunker-Ramo dual bifurcated contact, as originally patented; this is known from the Maxi-Switch Series 3100 derivative (soldered to the PCB instead of contact connection) and an unidentifiable transparent type found in a jukebox panel, also soldered
- Cherry reed
- Cherry M6 (or M5) pulse contact variant
- Clare-Pendar Series S950 illuminated
- CRC 02 snap-action reed
- Data Interfaces DI-100, DI-104 and DI-120
- Datanetics DC-50 double action, from the Apple III
- Datanetics DC-60 illuminated
- Fort Electronic Products Fero-Snap
- Futaba MR reed switches, also sold as George Risk KBR
- George Risk KBM-DIN (Mitsumi miniature mechanical)
- Cortron Series 555 and “intermediate” mechanical contact versions
- Magsat switches from the 1974 patents
- Mechanical Enterprises DN
- Micro Switch KB tactile and alternate action reed types
- Micro Switch SW secretarial shift
- Omron B2x tall Hall effect, low profile reed, and other patented variations
- Omron B2x alternate action and tactile variants (known only from a patent)
- Omron B3G (known only from a catalogue entry)
- IBM ribbon-driven membrane hammer (US patent 3662138)
- RAFI magnetoresistive
- RAFI RC 72 mechanical and original Hall effect
- TEC solid state keyboards
Many more types are known from patents. Types known only from patents are not guaranteed to have ever gone into production.
Not discovered in a keyboard
The following switch types have yet to be seen in a keyboard:
- Alps KKC Series capacitive
- Futaba MD-7 illuminated
- Fujitsu FES-5 (used in a variety of keyboard types, but never discovered)
- Fujitsu FES-8 Hall effect type (only seen in a catalogue photo)
- Fujitsu FES-9 Hall effect type
- George Risk KBLP
- Licon Series 550 original full height saturated core
- Magsat “flying magnet” switches
- Maxi-Switch 2700 series discrete plate-mount reed
- Mechanical Enterprises LFW (believed to have been seen, as loose NOS parts)
- Mechanical Enterprises Mercutronic (MC, SS and M-5 series)
- Micro Switch SW double action
- Oak Series 475
- Omron Hall effect, e.g. Omron B2H-F7W
- PED illuminated switches, as shown in the patent
- Raytheon KBSM tubular mechanical; one type is only known from a patent, and another is known from a single sample
- Sasse Series 25 Hall effect (only seen on an archived copy of the Sasse website)
- SMK JM-0400 reed
- TEC mechanical pulse switches
- Tipro SMK-style
- Tokai SPT-0101 and SPT0102 opto-electric