Can do but not all are controlling mach3 modes in fact only 3 mach buttons are controlled via trigger codes. Cycle start, feed hold and Reset. Some signals are sent to Mach inputs to inform about E-stop and to reset after E-stop etc.

Starting left to right.
#1 On/off switch and LED This just turns off 24v to control system so nothing can be turned on.
#2 Momentary Reset and Led which latches safety E-stop circuit(relay) on and Reset's Mach.(Trigger/Button)
#3 Oh shite Button connected to latching circuit and Signal back to mach informing E-stop(Input)
#4 Cycle start (Trigger/Button)
#5 Feed hold (Trigger/Button)
#6 Limit override