Hi Frank, this may be on your blog someplace already, both your blog and the forgotten NY sites are quite extensive and I could not find this one. It is on the side of a large apartment building in Astoria NY, I think the address is 31-28 31st Street. I have passed this rusty sign many times but never stopped to read it until today. It says “This building is adequately wired by H.K. Electric Co. More Buildings Rewired In Queens By H. K. Electric Co. Than Any Other Electric Company.” There is also an old phone number with a DE exchange prefix…definitely 1960s and before.
Dave Sanders, NYC
Hey Dave- Thanks again for a wonderful catch! According to the website below, this is the DEfender telephone exchange.