So why can't i trade between my Emerald and my FireRed, but it's cool if i trade between FireRed and Ruby?
"... That would be because, to trade, you need to have gotten the National Dex on both games. In FR/LG it involves completing the Sevii Island quests, and fixing Celio's machine.
In R/S/E, it's just beating the E4 if I remember correctly..."
I believe that
Flavaquil is only partially correct, and this is what I believe to be true;
In
R/
S you can trade with
FR at anytime of the game, as long as you've fixed the Network Machine in
FR. You do not need to obtain the NationalDex before hand, because trading with
FR/
LG is
how the NationalDex is obtained on
R/
S. However, in
E, you must first become the champion (ie. defeat the E4) before you can trade with
FR/
LG (before you are able to obtain the NationalDex). I also believe that you must first defeat the E4 in
E before you can trade for
any Pokémon not listed in the HoennDex, even if it
is from
R/
S. Meaning if you have not defeated the E4 on
E, and attempt to trade a Charmander (or any other Pokémon not listed in the HoennDex) by trading with
R/
S, it would still not work ( however, I could be wrong on that). Anyone, feel free to correct me if any of this information is inaccurate/incorrect.
I hope this helps at all?
~nguyende :)