Read it: https://sharktastica.co.uk/topics/m122_diffs
For those unfamiliar with it from before (I posted it on DT years ago but I couldn't find the thread to reply to and/or link here, lol), I categorised the major variants of M122s into a [then-four] Type System based on outward characteristics and features. This is not an alternative to generations, which people understood to describe quality and branding changes with Enhanced Keyboards (101 to 104-key Model M) over time such as backplate thickness and the text colour in the IBM oval badge, etc. My motivation for doing this was not being satisfied with how very early M122s were being called "Gen 1" and "Gen 2" when in fact they were produced concurrently with the later M122s for an entire decade! - it wasn't like one M122 style replaced the other, they were all supplemental and only released as IBM introduced new terminals. Simply put, generations understood for other Model M variants don't translate to the M122's outward appearance with only a single exception. Enter Types, which I specified to be a way of differentiating the outside and connectivity of M122 without implying one replaces the other.
Changes include:
- More photos
- Better descriptions
- Info on how each type maps to Model M generations
- Part numbers for each type added
- More info on what Unicomp did with Types 3 and 4
- More on any third party rebranded versions
- A new Type 5 defined covering Unicomp's POS/MSR M122s
Type 2 M122
Type 3 M122
Type 4 M122
Type 5 M122 Enjoy the [re]read!