Bell Home Interphone
My Aunt Doris had that in their Long Beach, MS house that they lived in from 1961 through mid 1963. I always thought it was a neat idea. The next house in Jackson they had two outside lines, plus intercom. That required a 1a2 system, like in an office.
Matt, it's too bad they hadn't ran the cabling through conduit to keep nails from being put through it.