I just bought a house that has speakers in just about every room downstairs. The connectors that run from the reciever to the wall are the strangest thing I have ever seen. Radio Shack had no clue what it was. It has 4 pins. The system was put in 40-50 years ago. Anyone have a clue what it is?
Four pins would indicate the likelyhood of either XLR (canon) connectors or DIN plugs. You can find either type plug at a decent electronics supply house. There were simple four pin speaker connectors used in the 60's that have four equally spaced pins and no locking provisions. If you have this type of plug, you might as well change these out to a binding post.