TI-99/4A Cartridge Expander
Navarone Industries produces the Cartridge Expander, which plugs into the game port of the TI-99/4A and allows up to three cartridges to be plugged in at one time.
The expander also contains a built-in reset button and a select switch that lets you change from one cartridge to another without plugging and unplugging cartridges.
The Cartridge Expander is available for $39.95.
510 Lawrence Expressway #800
Sunnyvale, CA 94086