Today, on what also happens to be the IBM PC's 44th birthday, I have launched a new wiki page! The 75-key and 87-key Model F keyboards for the IBM 3104 Display Terminal and 3178 Display Station! Often called the "blue switch" Model F, these are a part of the
IBM Base Keyboard lineage.
https://sharktastica.co.uk/wiki?id=modelfbase
3178 alone is quite well known, but 3104's version of the keyboard has a unique party-piece - DIP setup switches! Both 3104 and 3178 are ultimately 3270-style terminals, but where 3178 is a more traditional 3270 terminal that connects coaxially to a 3270 control unit, 3104 is placed in the 8100 product family and uses SDLC. The setup switches are primarily used for setting up the 3104's SDLC address, which the 3178 doesn't need and thus doesn't use DIP switches. That said, due to shared tooling, 3178 keyboards may have the setup switch access panel and the DIP switches themselves, but they serve no purpose. Later 3178 keyboard production deleted any space for them.
Whilst the 3104-3178 connection and that some of these keyboards have DIP switch support has been known for a while, I believe this is the first modern documentation of what makes 3104's keyboards unique and what the switches actually do. 3104s are far rarer than 3178, so it's been hard to find information by comparison, but I think I have made some good headway!
Enjoy!
