@52brandon The pins are available on the expansion header. They do make a breakout board for connecting external stepper drivers to the Duet2. See: https://duet3d.dozuki.com/Wiki/Duet_Wiring_Diagrams
The pins are available also on the Duet 0.85, but the wiring info has been removed from the documentation wiki. The 085 has a different pin setup for the expansion header.