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
- 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
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
- Tipro SMK-style
- Tokai SPT-0101 and SPT0102 opto-electric