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Keycap mounts

This section documents keycap mount forms, dimensions and compatibility between brands.




A number of switch series were customised by the manufacturer to accept different keycaps, including keycaps from rival manufacturers. Known instances of this are detailed below.

Series Customisation
Alps KCC General Instrument Series S950 is a variant of Alps KCC series that takes Clare/Pendar keycaps. Looking at the injection mould cavity numbers, either Alps provided the tooling (or the plans for the tooling) or produced these switches on GI’s behalf.
“Side-angled” cream shares a keystem customisation with KFF; in both cases, these switches are thus far only known from Facit typewriters from Sweden.
Alps KFF These share the same apparent keystem modification as KCC above.
Cherry capacitive Cherry’s pre-DIN solid-state capacitive switches were adapted to accept standard NCR keycaps, just as was Datanetics DC-50; this can be found in model B4TE-8301, built for an unidentified NCR terminal.
Cherry M7 M51-0131 is a variant of Cherry gold crosspoint with a custom mount. The reason for the custom mount remains a mystery. M51-0131 is a replacement part number for M51-0129, and one assumes that the previous version of the switch had the same custom mount.
Cherry M7 Style D itself is a mystery. So far, it has only been found in SAGEM keyboards. These switches are Clare/Pendar mount, which suggests that they were a custom part made for Sagem to permit them to use existing Belgian or French-made keycaps.
Cherry M9 Cherry M11 is a ground-up redesign of Cherry M9 created as a drop-in replacement to Datanetics DC-60.
Cherry M94A-1GBR is an M9 variant that takes the same keycaps as M51-0131; these are found at various sources in Bulgaria (both used and NOS).
Cherry M9 in general was widely used in typewriters, using at least one custom mount, marked “TA” in the M9 part number schema. M94A-18NI is another “TA” type, although it will accept Cherry MX keycaps.
Datanetics DC-50 NCR requested a custom DC-50 type that would use their existing blade mount keycaps, possibly from reed switches.
Switchcraft 315900 is a DC-50 variant that uses a standard non-keyboard pushbutton mount.
Datanetics DC-60 Evidence suggests that DC-60 was customised to accept MX keycaps (the cream DC-60 type); this has been found in the same keyboard as Cherry M1, where the latter was used for space, but with the standard DC-60 mount.
Digitran KM Digitran made a KM variant that accepted Micro Switch keycaps.
Micro Switch SD Plunger type C was a custom SD Series type for NCR. This is a blade mount, whose dimensions differ somewhat from the custom DC-50 switch made for NCR. It looks like it is the same stem as that of the illuminated switches with plunger-integrated LED, as though NCR only wanted a single keystem for all
Plunger type K is another custom type. This has been found in a Bunker Ramo keyboard. There is no indication that this was customised specifically for Bunker Ramo, but it is definitely a non-standard mount.
Mitsumi KAM Mitsumi KAM was adapted to take Marquardt keycaps