Data erasing device Robby-Bit and AEG-Telefunken DSR 200 (museum MSPT)

During research, I found these two nice devices.
A data erasing device Datenlöschgerät “Robby-Bit” in two versions (1979, 1986, latter one pictured) by German Algamatic Machinen GmbH.
Because of the new 1978 German privacy law, the data of magnetic tapes had to be erased reliable. This device erased all data within 3 seconds. Presented on 1977 CEBIT
Another interesting educational demonstation device is the 1967 AEG-Telefunken DSR 200 in a suitcase showing arithmetics and logical functions

Direct links are only valid for ~30 minutes, but a site search give more details
Museumsstiftung Post und Telekommunikation Berlin, Frankfurt, Nürnberg (Germany)