test card noun2 •(UK) A test signal, typically broadcast at times when the transmitter is active but no programme is being broadcast (often at startup and closedown).In 1967, the BBC needed a ‘test card’ for its new colour broadcasts, to be put on the screen when programmes were not being transmitted so engineers could adjust the quality of the picture. — 2013 •A card printed with various letters or symbols, used in testing vision. formstest cards
