Capture cards also called framegrabbers are used to pass-through the camera and presenter PC output into the Presentations 2Go recorders. Capture cards are either internal (PCIe cards) or external (USB3 boxes). Internal cards are often more stable since USB connections can suddenly fail, forcing you to reboot your system. However, USB devices are portable and can also be used on notebooks. "A frame grabber is an electronic device that captures (i.e., "grabs") individual, digital still frames from an analog video signal or a digital video stream. It is usually employed as a component of a computer vision system, in which video frames are captured in digital form and then displayed, stored or transmitted." (Wikipedia)