Hmmm… I’m more than a little sceptical here. What you read as “USA” in fact says “U-54”, a submarine number used by Germany in both WWI and WWII. The tag says “German WW1 Sub Phone From U-54 Salvaged 1921 Mar [then an unreadable date]”
I know little about what comms equipment might have been on board a WWI German submarine. However, what I do know is this. The brass plate says “de-energize before opening”, but in Dutch. I would have thought the German military (even if it sourced phones from the Netherlands) would insist on operational/safety instructions being in their own language… particularly since this is just a riveted-on plate that would be easy for the manufacturer to customise.
The WWI German U-54 was German-built, launched 22nd February 1916, commissioned 25th May 1916 and participated in the the First Battle of the Atlantic. In the course of 12 patrols she sank 1 warship, 26 merchant ships and damaged 3 others before surrendering to Italy on 24th November 1918 and was then broken up at the Taranto yard in Italy in May 1919. This doesn’t seem to sit easily with a claim the phone was salvaged in 1921.
