... time Full D1 DVR Product Introduce: The serial of DVR include 4 channels, 8 channels ... playback, support triple code remote network surveillance, data backup, parameter setting motion detection, I/O alarm ... compression2. Two USB interface, USB2.0 for data backup, USB2.0 for mouse operation3. Support ... Low voltage alarm 5V-30V High voltage alarmRS232Serial port, for extend use(16 channels)RS485Connect to ...