In 1989, Sunsoft came to SEGA with a proposal: What if people could play Mega Drive games together online? Wanting to make a splash in the market, the two companies teamed up and created the Mega Modem. The device brought online gameplay, downloadable games, news, contests, and even financial transactions to the SEGA Mega Drive!
https://youtu.be/pbWkjAFgR5Q