The e-Reader is an add-on device for the Game Boy Advance released in 2002 that can read dot codes on special cards and interpret them into data. Depending on the card, the data may contain either information or some type of Minigame. Several complete Nintendo Entertainment System games were also made available on special packs of cards. It took a total of nine or ten dot codes (two per card) to store the data of an NES game.
Four series of e-Reader cards were released for use with Animal Crossing. Some cards featured Mario-themed designs that could be uploaded into the game. One card even rewarded the player with a copy of Mario Bros. to place in their home.
The e-Reader was packaged with a classic NES game (either Donkey Kong Jr. or Pinball) and a "sampler pack" containing an Animal Crossing card, three Pokémon cards (Machop, Machoke, and Machamp) that allowed a minigame to be played, and a Game & Watch card that contained Manhole. Australian copies also included an Air Hockey game.
In 2003, Nintendo released Mario Party-e, a portable board game which included numerous e-Reader cards, some of which contained minigames. However, the e-Reader wasn't mandatory in order to play the main game.
Later that year, Super Mario Advance 4: Super Mario Bros. 3 was released. By linking a Game Boy Advance with the game to a second Game Boy Advance with an e-Reader, a player could use three special types of cards.
After 2003, Nintendo discontinued the e-Reader outside of Japan due to low sales. As a result, many cards (particularly the new SMA4 levels, a planned series of Game & Watch releases, and a set of bonus levels for Mario vs. Donkey Kong) were never seen elsewhere. Additionally, the Nintendo DS, while compatible with Game Boy Advance games, was not designed to work with the e-Reader, but it can be modified to fit in. It works on a Nintendo DS or DS Lite if the player were to open up the e-Reader and remove the Game Boy Advance Link Cable extension wires. The device was never released in Europe, and e-Reader functionality was absent in the European versions of the respective games. The device is compatible with the Game Boy Advance SP, however, it doesn't mount flush.
 Mario Classic NES Games