H.264 DVR Board, Hardware Compression, 480 FPS View, 480 FPS Record, 16 video channels, 16 audio channels, 16 sensor input (opt.), 8 relay output (opt.), 1 TV Video out, RS232 to RS485 PTZ Control (opt.), DVR Software - supports XP Pro, Win 7 Pro. (can be expanded to 32 ch with DV-XC164848S Slave Board)