Nintendo DS Game Cards are only compatible with WEP security, and are not compatible with WPA security. So while you can enjoy other online features of Nintendo 3DS with WPA security, you cannot play Nintendo DS games online with any system if your network is secured with WPA.
If your network is secured with WEP security and you want to play a Nintendo DS game online on your Nintendo 3DS system, please follow the steps below.
More about: Online Connections
© 2018 Nintendo.