I.R.I.S. 808 Digital Video Recorder - Manual (Page 36)

 MUTE (Mouse: )
Press this button to mute/not mute the audio.
 +/- (Mouse: )
Press these buttons to circulate up/down among the available split-window
displays.
 ENTER (Mouse: )
Press this button to display the GPS data if there’s GPS data fed to the DVR.
Please select the Type, Position, Background, Rows, and number of Characters on
the screen, and then press ENTER to display the GPS data, or ESC to cancel.
For software V6.12 or above, the user may enable/disable OSD display for
certain fields in main screen.
In GPS display, press ▲▼ for page up/down,
press ENTER to close it, or press MENU/SEARCH/.. to call up the
corresponding display as if there’s no GPS display.
4.4 Digital Zoom
The system supports X2/X4 Digital Zoom function. To use this function, press X2
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