don't forget 0-10v and 2-10v analog signals.

Never used 2-10V but I learned about 0-10V when someone approached me to design a device to input 0-10V position signal and output two phase-shifted sinusoids to retrofit to a controller that only took resolver inputs. We shipped a couple dozen of them to repair broken machine tools. Fun project, but not going to get rich from it!

I'm guessing that the 2-10V is to detect line break conditions?