>>42588549GSC can trade with gen1 as long as the pokémon exists in gen1, obviously, and as long as they don't know any moves that don't exist in gen1, but there is a move deleter to remedy that last point.
You can even use this teach moves to gen1 mons, to use in gen1, that they couldn't normally learn then.
Example:
>trade Aerodactyl to GSC>teach it Earthquake>trade it back to RBYAlso very useful to teach moves you've run out in gen1, like Ice Beam/Flamethrower/Thunderblot, if you ran out of the TMs in gen1, can just use trade them to GSC and use the (expensive) move tutor there and trade it back.
It even works emulated, i've used 2 sessions of BGB emulator on the same computer, very simple to set up.
