CardBus is a higher-performance version of PCMCIA.  A standard PCMCIA card 
will work in a CardBus slot, but a CardBus device won't work in a regular 
PCMCIA slot unless it is also backward compatible to standard PCMCIA.  Lots 
of network cards are CardBus compatible, since bandwidth is far more 
important than on something like a modem.

- Dave


> I've got a notebook which the 1.5.2 GENERIC_LAPTOP kernel detects 
> has a cardbus controller on it ... I've had a look in both the 
> 'cardbus' and 'pcmcia' manual entries but I can't see how these 
> differ ...
> 
> I'm wanting to get a modem and a network card functioning in these slots.
> Does anyone have any recommendations about useable devices? It seems
> that a number of 3Com devices are mentioned, but only specific models
> 
> the current network card I have (a NetGear FA410) isn't being 
> detected by the kernel (at least, there's no dmesg output that I can 
> see) ... apparently this card has worked in the past with this 
> hardware ...
> 
> Is CardBus a standard that preceded PCMCIA? Can one use PCMCIA cards 
> in a CardBus slot or CardBus cards in PCMCIA slots? I've seen a few devices
> listed as being both PCMCIA and CardBus compatible, but not all of them.
> 
> The supported list of hardware in the 'cardbus' manual entry is
> depressingly short, so it would be nice to know that I can 
> interchange these with no problems ...