The Mega Modem is a first-party dial-up modem accessory developed by Sega for the Sega Mega Drive exclusively in Japan on November 3, 1990. The peripheral was almost sold in North America as the TeleGenesis modem, but this plan was scrapped prior to release.
One of the few (only?) peripherals to support the 9-pin EXT port of the first-generation Sega Mega Drive, the Mega Modem allowed certain games and software to make dial-up connections through an attached telephone line. The peripheral itself also includes a built-in microphone and speaker for use with some software.
As the modem was limited to slow 1.2 kbps speed connections, only a handful of games use the peripheral for turn-based communication. In addition, the peripheral was used for other services (all requiring a monthly subscription fee):
- Digital game distribution through the Sega Game Toshokan / Sega Game Library software cartridge. With a 800円 monthly fee, players could download small-sized games to the cartridge for play, released between 1990 and 1992. Most of these games were exclusive to the service at the time, with most released later as part of the Game no Kanzume series and some official emulation services. It also included game soundtracks and an online newsletter.
- Digital home banking using the Mega Anser software cartridge and its bundled Ten Key Pad input peripheral (and optional thermal printer attachment). Specialized versions of the cartridge were made for specific financial institutions: Naisu-kun Mini, Osaka Ginkou no Home Banking Service: My Line, and Sumisei Home Tanmatsu.
- Receiving game statistics, both real-time and post-game, for professional baseball through the Nikkan Sports Pro Yakyuu VAN software cartridge. This utilized a monthly subscription fee and can show a visualized representation of each play as if it was a video game.
These concepts were later revisited for the Mega Drive using cartridge-based modems, including the Sega Channel (an official digital game distribution service using coaxial cable connections), the Mega Net (an online multi-use service for Brazil from Tec Toy, used for e-mail, banking, and chat), and the XBAND (an online multiplayer service from Catapult Entertainment).
Only seven retail games supported the Mega Modem peripheral:
As the modem was limited to 1.2 kbps speeds, most games use the peripheral for turn-based multiplayer. Shikinjou uses the service instead for distributing custom stages built with the built-in editor.
Both San San and GO-NET used the peripheral to connect to their own online service, both of which were later discontinued. Both were also the only play-by-mail games for the system, allowing players to continue their games at any time (even picking up the game on their respective PC clients).