deskthority

We should also mention that there was also a slight overlap of the model F and model M design.

Take a look at the model M50 key,

https://deskthority.net/w/images/2/2e/IBM_Model_M_50-keys_06.jpg

As you can see thats a model F top and bottom plate right there with a model M membrane inside it ...

I know this is more anecdotal than anything else, but every version I've run into with a DIN socket needed to be plugged into a keyboard to work.

How did the second batch work out?