"Smartphones are a common topic here on Edge of Emulation. In many ways, older portable gaming consoles like the Game Boy Advance provided the kind of functionality we expect from our modern devices. For example, there were several options for viewing multimedia content on the GBA. From albums full of MP3s to feature-length films, Nintendo's handheld seemed capable of doing anything, with the right peripheral of course. Despite most people mainly using phones as web browsers these days, their original purpose was to talk to other people by calling their number. Believe it or not, the GBA had this covered as well.

In July of 2004, a Japanese company called Digital Act released a specialized cartridge called the Campho Advance. The hardware inside provided the system with a miniature camera along with a telephone modem. It enabled the GBA to make and receive video phone calls via landline connections (POTS), in Japan at least. By connecting to the telephone system, it could dial others and send audio/video data in real-time. The product came with its own microphone earpiece since the GBA lacked any kind of native voice input."

...continue reading the linked article.