The EMS USB2 is an adapter from (up to two) PS2 dance mats to USB. It works under macOS Catalina on Stepmania Outfox without any drivers. I came up with the following Stepmania/Data/manualmapping.txt file to allow use of both dance mats, 6 buttons on each. However, I’m wondering if I did this right, since it has to map the arrows for one player to the ABXY buttons.
03000000430b00000300000012190000,EMS USB2 dual joystick,dpdown:b29,dpleft:b31,dpright:b27,dpup:b25,back:b17,start:b19,leftshoulder:b16,rightshoulder:b18,a:b28,b:b30,x:b26,y:b24,platform:Mac OS X,