The use and installation of PC Cards has not changed from previous models of the PowerBook.
The PC Card slots on the new PowerBook G3 are CardBus slots. This means that they can accept newer 32-bit PC Cards.
The lower PC Card slot has circuitry for handling video signals (zoomed video). Although a zoomed video card is a Type II card, it can only be used in the lower slot.
Zoomed Video
Zoomed Video is a method of displaying video signals sent from a PC card.
CardBus
CardBus is a 32-bit version of the PCMCIA PC Card standard. In addition to supporting a wider bus (32 bits instead of 16 bits), CardBus also supports bus mastering and operation speeds up to 33 MHz. CardBus cards include SCSI, Video in, and Video out (to a monitor) types of cards to name a few.
The slot supports both older 16-bit PC Cards, that work in other PowerBook models, and 32-bit CardBus Cards.
Note: Macintosh PowerBook G3 Series computers should not be confused with Macintosh PowerBook G3 computers. Though the names are similar, there are significant differences. For more information differentiating between the computers, read article 24604: "PowerBook G3, G3 Series: Identifying Different Versions"