What interface or breakout board do I need for Mach4?

You can find the cnc machine interface board here that works with Mach4: https://www.buildyourcnc.com/item/electronicsAndMotors-electronic-component-breakout-Mach4-mach3-USB-ethernet-Board This board will work with Mach3 and Mach4. The board is filled with a wealth of options and features, including the ability to connect up to 8 axes (motor drivers), pendant, LCD, many outputs and inputs, separate pins for limit switches , 2 relays, Ethernet and USB interfacing. Additional Information: