... transmission,mobile phone surveillance4. Support backup with USB Flash Disk, Movable hard disk,USB writer, Network5. Support 1channel. Main output, ... playback simultaneously(Optional playback channel)Recording BackupUSB,Moved Hard Disk,USB Writer,NetworkNetwork transmission8 Channels real-time ... for at most 50 DVR ),Free supply to use Dual StreamSupport(Main and secondary interchange)Group playAt ...