GVD E300 works as the control unit as well as the primary input and output unit of the whole VMS plaform that manages up to 8,000 channels and controls every aspect of the system. D300 works as the decoder to deliver high-quality videowalls for the platform. Each decoder supports two monitors, and each monitor can show multiple simultaneous videos. The decoder also allows a videowall to receive and show the alarms from a networked NVR.