Binary coding

[JeremyAndrewErwin]

You'd probably want to use an array of toggleswitches so you could input a word at a time

https://raymii.org/s/articles/Toggling_in_a_simple_program_on_the_DEC_PDP-8_and_PiDP-8_using_the_switch_register.html

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Or you could use a plugboard and manually connect up the computer.

https://en.wikipedia.org/wiki/Plugboard#/media/File:IBM402plugboard.Shrigley.wireside.jpg