Well, in conducting research for backtaps.com, I found out that Matawan still has diaphones up on their town hall, but I do not know if they are still in service. See google street view here:
https://www.google.com/maps/@40.4139427 ... 312!8i6656
Bob K
Matawan, NJ
Moderator:David
If it wasn't for growing up near the diaphone, I would not be on the fire department today!