Can You Transfer DS Files Between Each Other?

Like, lets say I have two DS Lites, and each have the same game inside of them.

One game cartridge has a file in it, while the other is a new cartridge I haven’t played yet.

Could I transfer the file over to the new cartridge? If this is not possible, is there a way to transfer DS files between 2 DS games?

Thanks.

like save-games?

Doesn't the DSi have an infrared or bluetooth? (can't remember, I sold mine last year)

If it doesn't, then the only way to transfer files is by using EDGE or R4DS and a PC, iic.

Since the biggest use for R4 cards is piracy, and they're illegal in other countries for this reason, they're not allowed to be discussed here.