The gamma 10 follows on a line a very successful punched card machines that were programmed by plugboards. In the gamma 10, the computer is programmed by software in the main memory. I guess it was a matter of marketing to include a plugboard as well. However, the plugboard was normally hidden behind a door.
The plugboard has a base plate that remains fixed in the computer and that provides the contacts for the plugs.
The plugs themselves are on an insert. This allows changing the plugboard program by replacing the insert without having to replug.
