The slots on the bottom of the GameCube are for a variety of different purposes. The most obvious use is for the GameCube’s internal power supply.
This slot also houses the console’s 802.11b/g wireless adapter, as well as a port for connecting a Game Boy Advance or a Game Boy Player accessory.
The other main purpose of the slots is to allow the console to be connected to a TV via an external video output. The GameCube can output video in standard definition (480i) or high definition (720p).
There are also two additional ports on the bottom of the console, which can be used to connect an SNES-style controller or a Memory Card Reader.
The bottom of the console also contains two additional ports, which can be used to connect other peripheral devices, such as a USB Keyboard and Mouse. Finally, on the back side of the console is a port that can be used to connect an extra power supply or a hard drive.