firewire bus/card counter

What's a good way to figure out how many dv cameras can be hooked up?

I thought maybe it was 1 per buss, and each buss would have 1 or 2
ports.  but I just found a 3 port card:

http://startech.com/item-specs/CB1394-3-Port-IEEE-1394-FireWire-CardBus-Adapter-with-Digital-Video-Editing-Kit.aspx

Its chip docs say:

"Three cable ports"
http://www.via.com.tw/en/products/peripherals/1394/vt6306l/

I am guessing that is 3 ports on 1 buss, so now I have no idea how
many cams I can hook to it.

Also, is there a spec that says 1 dv cam per buss, or is that some
side effect of typical implementation?

I am trying to figure out how many DV devices I can hook to one
laptop.  My current wizdum tells me 1 expansion card (pc-card/pci-e)
and 1 if there is an on board;  so 3 is not gonna happen ever.

I also guess I need to start looking at dv over usb, or maybe even web
cams.  for a user group meeting, low image quality isn't a deal
breaker, especially if it simplifies and drops the $price.

-- 
Carl K

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