That, my friend, is an outdoor phone outlet. I have never seen something like that before. It used to be that instead of having a little plug, it would have a big plug, and all four connectors would be spaced out like that. That is for a phone.
The cool thing here is back then that must have been swanky as fuck. Nobody had phones on the outside of the house!
Check out nuclear pulse rockets
https://en.wikipedia.org/wiki/Nuclear_pulse_propulsion