It used wifi. Can't remember if it also had IR communication, like the GBC. It's been ages since I had a DS, but I'm pretty sure that there was another handheld other than the GameBoy Color that had the IR stuff. Nobody used it though, because it fuckin sucked.

[–] Zangoose@lemmy.one 1 points 6 months ago

The DS did have an IR sensor but (I'm pretty sure, don't quote me too hard here) a majority of the local communication was using either wifi or a proprietary wireless connection using the wifi antenna/chip.

I specifically remember Pokemon Black/White having an IR quick-trade option where you had to put 2 DS's back-to-back and being really confused about it because it seemed useless since it took so long to actually work.