Darwin is the Parallel Port plugin for MACH4.
This part of the program is what provides the pulsing action if you use a parallel port. Mach4 was really intended to be using with a motion controller but depending on your situation you can get a machine to work over the parallel port using the Darwin plugin.
You just put the DARWIN plugin in the plugin directory: C:\Mach4Hobby\Plugins\
When you startup MACH4 you need to enable the plugin, go to MACH4, Configure, Plugins
There is a tab call Plugins, make sure Darwin is enabled and you should see a green checkmark. Not sure if you have to configure anything for that plugin but most plugins need some additional configuration, but right now you just need to make sure it is enabled.
Now go to MACH Configuration and configure your motors, Input Pins, Output Pins, Axis Mapping
Once you have those configured you need to configure the Motion Device, by default it is set to Simulation Device, you need to make Darwin your motion device.
If you have taken all these steps MACH4 will move your machine.
Russ
Now you need to configure MACH4