Alps SKCL/SKCM Series
The Alps SKCL and SKCM switches, sometimes also called Alps Bigfoot or Alps CM switches, are the most common type of Alps switches used in computer keyboards. The “bigfoot” nickname was coined by the administrator of the Japanese website Mousefan, and has since become the most popular term used when referring to these switches. Alps referred to the tactile variants as SKCM switches, and the linear ones as SKCL in their brochures.
Alps microswitches have part numbers beginning SK.
Alps uses the SKCL nomenclature to refer to a certain type of linear keyboard microswitch, and the SKCM nomenclature to refer to a certain type of tactile keyboard microswitch.
First introduced as early as 1984, the Alps SKCL/SKCM series has been one of the first commonly available, compact-design keyboard switches. Over the years there have been several variants of the keyswitch, including changes in colour and design. Early variants of the Alps switch did not carry the Alps logo on the top part of the case, and only had it stamped in on the switch bottom. The most major difference being an entire redesign of the inner workings. These two different types of switches are generally being referred to as complicated and simplified.
In addition, the terms "ALPS" and "Alps" are widely used to refer to a large number of clone switches manufactured by other companies, in particular Xiang Min. Many clone switches are visually indistinguishable from Alps Electric's own switches; the only way to be sure is to open the switch and examine the mechanism.
The first versions of the Alps switch are termed "complicated", owing to the contact assembly being more complicated than the later simplified switches. Complicated switches contain the electrical contact plates within a plastic block termed the "switchplate". The actuation leaf of the contact mechanism runs down the side of the switchplate.
This block initially extended down to the base of the shell; this is a known as a "long" switchplate. Later complicated switches, in particular the black tactile switch, used a "short" switchplate that does not extend to the base of the shell. There is speculation that reducing the length of the switchplate degrades the smoothness of the switch.
The contact mechanism adds numerous extra parts to the switch compared to simplified switches.
When looking at original Alps SKCL and SKCM switches, it is also safe to say that switches without a logo are generally the older, complicated variant. Clones do not have the Alps logo on them at all.
To cut costs, the contact mechanism of the switch was simplified: the self-contained switchplate assembly was removed, leaving just the two metal contacts. Variations of this design have become known as both Simplified Alps Type I and Fukka, the latter being a misreading of "福華" ("Fuhua"). Alps Electric worked in close partnership with the Taiwanese manufacturer Forward Electronics (Fuhua), and the Alps Taiwan factory was taken over by Forward Electronics, who continued to produce the simplified design as the Fuhua Alps switch until it was discontinued in 2012.
Simplified Alps switches seem to have first appeared around 1988.
The Alps CM lock switch is a latch switch used for the Caps Lock key on some keyboards, for example the Apple M0116.
The compact variant is a linear switch with reduced front-to-back depth; it does not appear to be keycap compatible.
Various manufacturers including Xiang Min and Strong Man produced copies of Alps switches, a few of which are externally indistinguishable from real Alps switches. Many of these copies are externally indistinguishable from each other. Xiang Min XM switches are still in production. Most currently known copies are also considered "simplified" switches, as very few contain switchplates. Some switches are pin-compatible with Alps switches: they can be soldered into keyboards designed for Alps switches, and vice versa; these switches are known as "clones".
Traditionally it has been held that there are four main clone switches, referred to as Simplified Alps Type I through IV. Type I, as mentioned, is not a clone: it is Alps Electric's own simplified design that was later divested as Forward Electronics's switch.
However, the number of known copies is considerably higher.
When examining unbranded Alps-style switches on a keyboard, the key detail to look for is the number of side tabs that support the switch. If the switch has four small tabs (a so-called "four-tab clone"), it is certainly a clone. If the switch has two long side tabs, it is relatively likely to be genuine Alps (especially if the board dates back to the 1980s), but there are copies of the switch with long tabs.
Alps switches came in many colour variants, most of the time used to define the switch type. Despite being a pretty good rough guide, Alps did not always stick to their colour codes and seems to have changed colours randomly for reasons unknown. All of the colours listed below refer to the slider.
|White: The white Alps CM switch is one of the most common Alps switches. It is a clicky and tactile switch existing in both complicated and simplified variants. Early versions did not show the Alps logo on the top part of the case and seem to be identical to the older blue Alps switches. The newer variant, has a slightly different contact plate.|
|Black: The black Alps CM switch is a tactile, non-clicky switch. They normally have the Alps logo embossed on the top part of the switch casing. The most common keyboards utilising this switch are those from the Dell AT101 family.|
|Blue: The blue Alps CM switch is the first switch of the CM series introduced to the mass market. It is a clicky and tactile switch. Blue CM switches generally do not have the Alps logo engraved on the top part of the switch case. This switch seems to have been mostly replaced by the almost identical white switch starting in 1987 or earlier. Some people believe the blue switch to be smoother in feel than the white one.|
| Cream (tactile): Off-white "cream" coloured sliders with rubber dampers that dampen both bottoming and release.
The most common keyboards utilizing this switch are the Apple Extended Keyboard II (M3501) and some keyboards from Silicon Graphics such as the "SGI Granite" (9500900). A less common variant of the switch has a white slider. At least one keyboard (the HP C1414A AT) has cream sliders without the dampers fitted.
Less common colours
|Green: Linear, with LED cutout.|
|Grey (complicated): Linear, with LED cutout; in the region of 120 cN.|
|Grey (complicated): Linear with higher resistance, for space bars.|
|Grey (simplified): Clicky. Alps-branded, but it remains unconfirmed whether Alps made these before Fuhua took over (see Fuhua Alps).|
|Grey (simplified): Tactile. Alleged to exist in some Strong Man SMK-85 keyboards; not confirmed.|
|Dark grey: Alps CM lock, used for caps lock. Sighted with 'ALPS' embossed into the housing.|
|Cream (lock): Alps CM lock|
|Salmon or Pink: Tactile. Sighted with 'ALPS' embossed into the housing.|
|Bright yellow: Linear, with LED cutout.|
|Taxi yellow: Clicky.|
|Brown: Tactile; also linear, with LED cutout.|