I have a picture of my grandfather, circa 1930. He is standing at a desk that is covered with what appears to be some type of testing equipment. His testing equipment is hooked up to a box slightly larger than a 1# loaf of bread with knobs. The box is wooden. On the wall is a pennant that says NRI. Does anyone have any idea what that could stand for? We thought, perhaps, National Radio Institute but I can find no information on it. Thank you.