Older video game console and home computers generated a nonstandard NTSC or PAL signal which placed both fields on top of each other.
While nonstandard signals were common, i.e. using slightly different horizontal or vertical refresh rates, only outputting one field type fits within the defined standard & was in practise long before people had computers or video games in their own homes.
Outputting identical odd/even frames is different to only outputting even frames, the first is referred to as double strike (Amiga modes had names that started with DBL) while the latter is generally referred to as non interlaced.
As 240p over component is different to 240p over composite (or non interlaced), your tv might support one but not the other.














