Professor Gary told us:
Professor, when I left Frankfurt (worked at the Technical Control Center behind the I. G. Farben building, January 1979-June 1982) that same switch was still in use there. It was very temperamental but the biggest problem we ever had was those damn "war" circuits. The ring-down lines for 5th Corp out to all of the lower command HQs. Mr. Harold, the line tester, would log them out of service every morning when the only problem was getting someone just to be there to answer the dang thing.
By the way, did you know Mr. Harold? The joke we had there was he, Mr. Harold, was doing the same thing for the US Army that he did when he worked for the Nazis.
Can't wait to get back to Frankfurt to look around and visit some of the old hang outs with the wife.