I mean, when browsing teletext with your decoder you’d get the TV channel’s audio unless you muted it. Did you mean “teletext demo” programs that didn’t require decoders and were often broadcast just before signoff? In Czechoslovakia before 24-hour TV, we’d get classical music, signoff, the anthem (pre-1989), and then a test pattern with a radio station. Video of this
I’d imagine some teletext demo programs did have radio playing.
Sometimes there was music in the background, some sort of radio. Don’t stress over it, that was not a technical endeavor.
I mean, when browsing teletext with your decoder you’d get the TV channel’s audio unless you muted it. Did you mean “teletext demo” programs that didn’t require decoders and were often broadcast just before signoff? In Czechoslovakia before 24-hour TV, we’d get classical music, signoff, the anthem (pre-1989), and then a test pattern with a radio station. Video of this
I’d imagine some teletext demo programs did have radio playing.