... real time recording2.Video input:4ch BNC,Video output: 1ch BNC, 1ch VGA3.Audio input:1ch RCA,Audio output:1ch RCA4. Playback image ... playbackSupport 1to 4 ch playback simultaneouslyBackup waySupport HDD,Network,USB,USB-RW backupModelDH8704Video storageHDD ,networkVideo input4ch BNCAudio ... input1 ch RCAVideo output1ch BNC,1ch VGA(support 800*600,1024*768,1280*1024, ...