I’ve been working on and updating my article on the differences between 122-key Model Ms, which is the four-type system I use on my website and its IBM and co keyboard database. If you’re curious about the variation amongst M122s, feel free to have a read!
The backstory behind this endeavour was that when I was designing the model for my part number database, I wanted distinction for M122 part numbers that were more clear cut than the generations people are already familiar with (as explained below, there’s a difference). As such, I settled on this classification system and I was able to make an article for my IBM keyboard “knowledgebase” from it!
Note: these types are not the same as generations. The type system describes the differences in outward form-factor and feature set, whereas the generation system typically describes production quality differences (such as assembly backplate thickness, branding/badges, etc). Typically, part numbers only describe a single type of keyboard, however, they could be made to the internal specs of different generations throughout the production period.
Legit this is one of the best notes in regards to vintage boards, part numbers, and internal generational specs I’ve seen. A lot of people really don’t know this and it can be super useful/helpful!
I’ve rewritten and reworked this page quite a bit. The descriptions for each type are now more detailed, a few more photos have been added, example systems the keyboards shipped with have been added, and I’ve also mapped the types to the possible generations they can be. To reiterate: types = feature set, generations = production quality/values.
