[ARC5] Trivial question. Meaning of "SCR"

[gordon white]

     If you look back to the beginning of military radio, SCR = set, 
complete, radio. There was a lot of military jargonof the same ilk. AN 
("Army-Navy) of course came in during WW II and was more explanatory.

"Signal Corps Radio" doesn't cut it since there were non-Signal Corps 
radios, believe it or not. And even if you wanted to go that way, SCR 
would make no sense, since they were defining a complete set or radio 
system, made up of Basic Components.

  - Gordon White