NEC LT240K User Manual page 40

PROJECTING AN IMAGE Selecting a Source
Detecting the Signal Automatically
Press and hold the SOURCE button for a minimum of ONE second,
the projector will search for the next available input source. Each time
you press and hold the SOURCE button, the input source will change
as follows:
RGB1 RGB2 Video S-Video Viewer
If no input signal is present, the input will be skipped. When the input
source you wish to project is displayed, release the button.
Press the ENTER button.
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