Video surveillance recorders: recording devices suitable to collect and store cameras video signals; recorders may be divided by supported technology into DVR for Analog cameras, NVR for IP Network cameras, HCVR for HD-CVI cameras, AHDVR for AHD cameras, TVIVR for TVI cameras and Hybrid HVR, hybrid devices that support more than one technology among AHD, IP, Analog, TVI, HDCVI. The acronym DVR may also be often found preceded or followed by the reference technology: Analog DVR, IP Network DVR, AHD DVR, TVI DVR, HD-CVI DVR.