They open the pump face, unplug the back of the existing reader, plug the front of their skimmer into the back of the existing reader, and connect the first plu

They open the pump face, unplug the back of the existing reader, plug the front of their skimmer into the back of the existing reader, and connect the first plug into the back of their skimmer. It goes from ? --> reader to ? --> skimmer --> reader The face of the pump appears unchanged (unless they broke a security sticker and were unable to replace it)