I have now done my homework and I am a little bit wiser on this system. It's called an "ADT" (Swedish; Alfanumerisk Textskärmsterminal), roughly translates to "Alphanumerical Textdisplayterminal". It was used throughout the Swedish Coastal Artillery (mobile and fixed batteries) in the STRIKA 85 system, which was taken into service in the early 1980s and in use til the year 2000. Made by the Swedish company Ericsson.
Source (In Swedish), *page 270*
http://fht.nu/Dokument/Marinen/marin_publ_dok_strika_ver_3_5.pdf
https://digitaltmuseum.se/021027456554/dator
![https://i.imgur.com/EJTAyhal.jpg](https://i.imgur.com/EJTAyhal.jpg)