This reel to reel machine was removed from a captured WWII German submarine. It was used to record reports at a very slow speed: 1-7/8 inches per second and maybe even slower. Then, it would surface to allow the report to be transmitted, running the playback at 30 ips (16x recorded speed). That way a sixteen minute report could be burst-transmitted in just one minute and minimize the sub's risk for detection on the surface. The operator on shore would record at 30 ips and then playback at 1-7/8. True 1940's era file compression!
An early version of burst intel transmission, performed since the 1960's electronically. The recording medium was probably oxide on a thin paper backing, maybe on an early polymer backing, or even on a wire. Wire recording was tough to edit without a soldering iron.
The Germans also used tape recording for time shifting, recording Hitler's and other's speeches and national concerts for playback to make it appear that their leaders were in a place where they actually were not when the event was broadcast: the very first TIVO!
Photo from an exhibit at The Pavek Museum.
