I'm trying to interface my Arduino Uno with a typewriter (smith-corona sl 460) I picked up in a garage sale a year ago. My final goal is to make it so I can type in something on the serial monitor on my computer, and have it come out via the typewriter. I'm going to try to do this by wiring the output pins on the arduino to the keyboard input pins on the typewriter. However, I can't make heads or tails out of this cable coming from the keyboard, and if there are any silkscreen labels, they are on the other side of the board, which I don't want to flip over - I still want this thing to be operational if the hack doesn't work. How would I go about figuring out what line of the cable did which? I have, as I said, an Arduino Uno, as well as a multimeter, and a fairly basic pocket oscilloscope, with no digital analysis or even that much memory past a capture function. If I'm trying the wrong sort of approach for this project, please let me know.
A picture of the cable and the microcontroller:
A picture of the whole board: