I'm looking for the name of a black and white 1950's science fiction movie. It starts out with a man that finds a small black box with a little cone on one side at a construction dig site. A little boy, I think his son, asks to keep the box. He takes this box home and somehow drops it and it shatters into pieces. He goes to sleep with a piece of the object in his hand and next thing we know he teleports to a different world. He convinces someone in his family about this experience and takes them to this other world and they find many of these black boxes. They find a dead humanoid with a headgear that has a wire which is connected to one of these boxes. They put the head gear on and find out information that is contained in the box. The information they learn is about two different planets which are at war.
They then are able to teleport from planet to planet when they stand on a round platform. I thought it was called the Terminots or something like that.