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Alps PCB codes

Alps PCB codes are numerous categories: “CB”, “CH”, “CN”, “12K”, “11K”, “AAA” and “PWB”. See Alps keyboard codes for more examples.

The meaning of 11 and 12 (in the 11K and 12K codes) and 54, 56 and 57 (in the AAA codes) is not known. In SMK part numbers, the leading code identifies the part classification, e.g. 401 for PCBs and 221 for relegendable covers. In which case, this number should not change. It could indicate the plant used, although that would put the PCBs for Japanese-made and Korean-made keyboards into the same plant. It is curious that the codes changed around the same time as second-generation SKCL/SKCM switches were introduced.



CH codes seem to be from the 1970s. Examples:



12K codes appear to span from 1980 to around 1988. The two letters after the number 12 are the first two letters of the series name, e.g. “12KE010C” denotes an elastic contact (KE) series keyboard, specifically KEH series in this instance (a TRS-80 Model III keyboard variant). 12KC covers the “switchplate” types. 12KF covers the switches with plain metal contacts.


The meaning of 11K is unclear, and there are very few examples. The first is an unspecified keyboard that could be an Alps-made Olivetti keyboard. It is simply described as being “similar” to Olivetti L1 ANK 1426. The Alps-made PCB is the only part of it that was ever documented; the PCB has code is 11KF013A, where KF implies a mechanical switch without a metal foil contact assembly. Helpfully there are no photos of the switches or the rest of the keyboard, so it remains a mystery exactly what this was, but it is suggested to be another ANK 1426.

The second example is the keyboard for the NEC PC-6001. This is also insufficiently documented. The keyboard has a PCB and discrete domes, that one can only guess just rest on the PCB and are held in place by the housing. This PCB has code 11KE083D, where KE denotes elastic contact. 11K here may denote some kind of fully-custom model that is not part of any standard Alps series, which would also be the case where Alps is second-sourcing an Olivetti design (the first example).

Code 11KE086A is used on an elastic contact keyboard also made for the Olivetti ET 121 typewriter. Unlike other Alps switch models, the rubber dome bridges contacts on the PCB, and is held in place by a clip-on cover on the bottom of the switch. Identical switches (colour notwithstanding) were also made by SMK for the same model of typewriter.


These codes typically start 54AAA or 56AAA, but 57AAA has also been seen, and AAB might also exist. Unlike the preceding 12K codes, these appear to offer no details about the switches used in the keyboard.


This denotes “printed wiring board” and is seen on Alps USA PCBs, e.g. Apple Extended Keyboard, Apple Extended Keyboard II and Zenith 163-73.