Jumper Pak

Description

The Jumper Pak (Terminator Pack in Japan) is a small module that shipped inside every Nintendo 64 console. It fits into the memory expansion slot on the top of the N64, beneath a removable cover. The N64 was designed with the expansion slot connected to its RDRAM (Rambus DRAM) memory bus. For the system to operate correctly, the electrical signals on that bus need proper termination to prevent reflection, noise, and instability. The Jumper Pak provides this termination and doesn’t contain memory, it simply closes the circuit and stabilises the bus.

With the Jumper Pak installed the console can operate with its standard 4 MB of RAM. For most games, this was sufficient. However, certain later titles like Donkey Kong 64, Perfect Dark, and The Legend of Zelda: Majora’s Mask required the Expansion Pak, which replaced the Jumper Pak and doubled the system’s RAM to 8 MB.

Because the Jumper Pak was necessary for the console to boot, removing it without inserting an Expansion Pak would leave the system unable to run. Nintendo 64 consoles shipped with a warning label on the top of the Jumper Pak indicating it should not be removed. In practice, it was rarely interacted with by players, except when upgrading to the Expansion Pak.