Dell 5100cn Color Laser Printer - Manual (Page 71)

4. Remove the controller card from the printer by the handles.
5. Place the controller card on the table so that its edge hangs over the edge of the table and the controller card is
horizontal. Hold the multi protocol card so its connector is aligned with the slot on the controller card, and push it
down.
6. Align the two protrusions with the holes on the controller card, and then tighten the two screws from the back side
of the controller card.