QSDR174RTC User Manual42.2: Rear PanelItem Number Name/Symbol Description Function1 VIDEO INPUT1-4 Video Input Ch1-4 (BNC Interface) Connection2 AN1, AN2,AN3, AN4 Audio Input CH1-4 Audio Signal Input (RCA Interface) Connection3 AUDIOOUTPUT Audio Output Audio Signal Output (RCA Interface) Connection4 USB Port USB Device (Flash Drive, Hard Drive) Connection5DC12VPower Port Power Supply - DC12V 3A6 USB Port USB Mouse Connection7 LAN Ethernet Port Intranet and Internet Connection (RJ-45 Interface)8 RS485 AlarmPortRS485 Interface9 Alarm SensorPortAlarm Sensor Interface10 Alarm Port Alarm Interface11 Power Switch Power On and Off12 VIDEOOUTPUTVideo OutputConnectionVideo Out Connection O