Morning, In 2001 it was fully possible for Capcom vs. SNK 2 Dreamcast players to fight their PlayStation 2 counterparts in Japan. Yes, that means Capcom solved the cross-platform issue 18 years ago. This is (mostly) undocumented. I want to fix that. My understanding is that Capcom got together with a company called KDDI to create a "matching service". Consoles would connect to the internet, access these KDDI servers, magic would happen, and "low latency" hadoukens ahoy. For the Dreamcast, the built-in modem was used. For the PS2... Capcom bundled in an external USB modem. Unless you didn't need one. I have no idea whether it works with Sony's official network adapter. There's also talk that this might have worked with the NAOMI arcade version too, but I don't know. Likewise there's speculation that there was Dreamcast Broadband Adapter support, but I can't confirm that either. What I do know is that all of the servers have been shut down, and there is currently no means of getting any of this old kit to work. The Xbox and GameCube "Capcom vs. SNK 2 EO" ports from 2003 are not compatible. Kidou Senshi Gundam: Renpou vs. Zeon & DX also appears to have had cross-platform play. Even less has been written down about that. Fact check etc.