Thank you! That answers my question. I was hoping to replace the joystick in MAME with a dial control.
Thanks for the additional information. Frontline has a peculiar rotary controller that was only used in a few games. There is a guy on eBay that sells a modernized version of that controller.
I really loved that Frontline game in my youth and was hoping to recreate the experience through MAME. I'm in over my head and will give up at this point.