Frame Grabbers were invented in the early days of machine vision to connect analogue cameras with NTSC and PAL output signals to minicomputers that needed digital signals placed directly on data buses for digital memory storage. Even after the transition to digital cameras, there was still a mismatch between digital video outputs and computer-input bus requirements. Something was required to feed video data streaming from the camera into the computer's memory. This requirement was met by a piece of hardware known as a frame grabber, which plugged directly into the computer's motherboard and provided a physical port for connecting the machine vision camera.