57The other ways is to press power button on the front panel for at least 3 seconds, system willstop all operations. Then you can click the power button in the rear panel to turn off the DVR.4.1.4 Auto Resume after Power FailureThe system can automatically backup video and resume previous working status after powerfailure.4.1.5 Replace Button BatteryPlease make sure to use the same battery model if possible.We recommend replace battery regularly (such as one-year) to guarantee system timeaccuracy.Note:Before replacement, please save the system setup, otherwise, you may lose the datacompletely!4.2 Live ViewingAfter you logged in, the system is in live viewing mode. You can see system date, time andchannel name. If you want to change system date and time, you can refer to general settings(Main Menu->Setting->General). If you want to modify the channel name, please refer to thedisplay settings (Main Menu->Setting->Display).Preview ControlThe preview control function has the following features.z Support preview playback. In the preview desktop, system can playback previous 5-60 minutes record ofcurrent channel. Please go to the Main Menu->General to set real-time playbacktime. Support drag and play function. You can use your mouse to select any playbackstart time. Support playback, pause and exit function. Right now, system does not support slow playback and backward playback function.z Support digital zoom function.z Support real-time backup function.You can follow the contents listed below for the operation instruction.Preview control interfaceMove you mouse to the top centre of the video of current channel, you can see system popsup the preview control interface. See Figure 4-6. If your mouse stays in this area for morethan 6 seconds and has no operation, the control bar automatically hides.Figure 4-61 Recording status 3 Video loss2 Motion detection 4 Camera lock1 2 3 4