I have a similar story. School calls me and says that if they don't answer a call within three rings it gets disconnected. I tell them I'm going to call and don't pick it up. Sure enough after about three rings something picks up the line and I hear kids laughing and talking. Long story short the elevator company connected their elevator phone (that never was connected for years) to the nearest dialtone- a 66 block in the machine room, clips 1&2 which just happened to be T&R for extension 10 on their Partner system. So the extension would ring and the elevator phone was programmed to pick up on the third ring. Fortunately I happened to call when the elevator was full of kids or it would have taken a lot longer to figure that one out.
-Hal
