Where (in the USA) can I buy a card supported by isdn4bsd??

[Josh Osborne]

>You can use AVM's active cards (eg. the PCI B1). They are a bit
>more expensive, but have downloadable firmware for both sides of
>the pond. Work with i4b quite nicely, since they don't use the
>software ISDN stack for protocol implementation.

Oh?  Are there any features of i4b that are lost when you don't
use it's software ISDN stack?  And is the performance any better
or worse?