usb camera input

I have a home security setup with BI that uses many different cameras. I have set up a tablet as kind of a central system viewer in my living room. I recently decided to add the USB cameras on mine and my wife's computers (which the kids are not allowed to use). My question is, is there a way...

I know this is an IP camera forum but please let me throw this at you all. We are helping a friend who has 20+ analog cameras and I'm looking for USB port import equipment cords, whatever to hook those cameras into his new PC and into Blue Iris? Has anyone here ever had any luck with...