What accessory let players trade Pokémon between two original Game Boy games?

The Game Link Cable let players trade Pokémon between two original Game Boy games.

Pokémon Red and Green were designed around communication between players. By connecting two Game Boy systems with a cable, players could battle or trade Pokémon. Trading was essential because each version contained species that could not be obtained in the other without exchanging with another game.

The cable made Pokémon’s collecting idea social rather than purely individual. It also helped distinguish the series from role-playing games that were played entirely alone. The original Game Boy hardware supplied the physical connection, while the Pokémon software handled the battle and trading functions.

The Game Link Cable is often confused with Nintendo accessories for later systems. The Transfer Pak connected Game Boy cartridges to Nintendo 64 games such as Pokémon Stadium, but it was not the original trading accessory. The Super Game Boy played Game Boy cartridges on a television through the Super Nintendo and did not connect two Pokémon cartridges.