portable dvr ,mini dvr 4 channel USB DVR/1 channel audio Main Feature:1. 4 channels video input in one card, the maximum display/recording rate is 25 fps under PAL format, and 30 fps under NTSC format. 2. 1 channel audio input. 3. 4 screen display modes are available. 4. Multi alarm triggering method: sensor, motion, video loss, and HDD space shortage. 5. Support schedule recording mode, ...