We moved into a new house and there was a jack in the kitchen and bedroom. In the living room there is what appears to be a phone wire attached to a gray plug. We took the plug out of the wall and the other phones still work. We removed the wires from the plug; they are red, green and yellow. We hooked it up to a phone jack, red to red, etc. It doesn't work. Has anyone seen this type of phone jack? Or maybe it's something else? The doorbells still work--that was one other option we thought of. Thanks.