In former GDR (Eastern Germany) there was a computer show on the radio where programs were broadcasted this way. Listeners could record the programs with tapes an then run them on their computers.
Ah yes, we had something similar in Romania too, only that it was on national television. I got so many games and programs from it. Since they had reception everywhere in the country I was able to record them from the country side or a monastery too.
Same in Poland, good memories (not such good government though)
Sounds very much like BASICODE[1] which was used to broadcast e.g. tax return software on national public radio in the Netherlands back in the 1980's