... 8-Channel Standalone DVR AST-DVR0804LBH.264 Algorthm, Pentaplex, Support Internal CD / DVD-RW , USB Backup, SATA portIN:16 Ch Video,4 Audio ... , bios version, on-line user etc.VideoVideo Input4/8/16 channel, BNC, 1.0Vp-p, 75?, looping(optional) ... , 30KΩBidirectional Talk Input1 channel, BNC, 200-2800mV, 30KΩAudio Output1 channel, BNC, 200-3000mv, 5KΩAudio CompressionG.711Video Detection & AlarmMotion ...