QSDF8204 Digital Video Recorder User Manual82.3 Rear PanelLayout subject to change, may be slightly different from your model.The rear panel sketch and interface buttons are shown below:Items Names Functions1 ALARM IN Connect to external sensor 1-4.2 ALARM OUT Relay output. Connect to external alarm.3 +5 V and GND +5 Volt and ground connection4 COM port For debugging or data entry5 RS485 Connection for PTZ cameras6 RJ45 PORT Connection for network or internet7 Not Used8 AUDIO IN Audio input, connection for MIC or other audiocapture devices9 AUDIO OUT Audio output, connection for speaker10 S-VIDEO S-Video output, connect to monitor11 VIDEO OUT Connect to TV or monitor12 VIDEO IN 4ch Video inputs13 POWERINPUT DC 12V14 USB PORTTo connect USB mouse for control or external USBdevices like USB flash drive and USB HDD forbackup or firmware update15 FAN For cooling the device