EAR 834P MM/MC options help

I recently acquired an EAR 834P. There is a push button in the back to select between MM and MC with a label that has MM on top and MC at the bottom. Maybe there’s an industry standard for defining whether the button being pushed in or out corresponds to the top (MM) or (MC) but heck if I know. Anyone know whether the button pushed in is MM or MC or vice versa? Not clear in the manual.