Hey Terry, thanks for the reply. The subject of my inquiry is not an AE 50. I know AE 40s and 50s. They were the bread and butter of my era in the 1960s. No, this phone, in the simplest explanation, looks like an AE 80, upside down and hanging on the wall instead of sitting on the table. I don't recall where I acquired it since it has collected dust in my basement for a quarter century, and I have never seen another one like it. I was gonna rip the innards out to refurbish an AE 21 but now I'm thinking it might be a keeper.
I can text a pic to you if you leave your cell number with me.
ERIC