DNC4U has a wizard that you run to help set up the parameters for each particular machine. I must be getting some kind of connection because it's saying there is data coming from the machine, but it's just garbage. I'm thinking some gasoline and insurance money about now.
The "box with the keyboard on it" is usually just the pendant station that will have the CRT display and keyboard, as well as a couple circuit boards to interface pushbuttons and lamps. You want to find the card rack, which is about 12" X 10" and maybe 8" deep. It will have an aluminum cover and will say "Autocon" or "DynaPath" on it. It should have a slot with 5 separate ports - X, Y, and Z axis command and feedback in ports 1, 2, and 3 respectively and the spindle command connector in port 5.
DynaPath always sold Lagun an "unbundled" control. Basically the control rack and the front panel stuff. How Lagun put it in the cabinetry probably varied, so it's difficult to be specific.