Marconiphone 701 Dual Standard television receiver, 1936
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Television – like its predecessor radio – is a child of many parents. It is based on a number of inventions that were made in various countries at differing times. Not every country has developed television in exactly the same way.
Both in the pioneer years of television before the Second World War and in its full development afterward, countries developed different standards for how many lines would make up the television image: 405 in Britain, 819 in France and French-speaking Belgium and 625 in the rest of Europe. On the eastern side of the 'Iron Curtain' (except East Germany) line standard was the same but the sound was broadcast on a different frequency so that western TV could be seen but not heard, or vice versa. To create television that could be viewed across borders in western Europe meant costly conversion, either by the broadcasters themselves when they received signals from other nations, or by users on expensive multi-norm television sets.
