My 1970 house has this strange little window. It is in between the laundry room and kitchen, right next to the door. It has a hookup that looks like it is for a landline phone. Im wondering was this just a little window area for a telephone? It has always struck me as odd and Ive never seen another one like it. I added the clear plastic you are seeing, it was just open when we moved in. You could stick stuff right through it, like a serving window. Does anybody know what its true purpose was?