... 1 SATA port HDD MAX 2000GB 4CH security DVR, 4-CH DVR, cctv dvr4CH video and 1CH Audio real ... Recording and display4CH D1Video I/O: 4/1Playback: 4RS485: supportAudio I/O: 1/1 4/1Alarm: N/AHDD: 1*2T ModelHSD7504VHSD7504AVSystemMain ... /ContinuousPlaybackPlaybackMulti CHs playback simultaneously, pause, stop, rewind, fast play, slow play, next file, previous file, repeat, shuffle, backup selection ...