Through design I have 9 CCTV cameras, so with my 8 port card I left one out.  I have a spare single port card, but have not tried it, but it doesn't do hw compression so I wouldn't use it anyway.  I would either get a 4 port card, and the software would "just work" with 12 active ports, or I could start converting to network cameras, which is another question in a previous post.

thx