Most Epson projectors can be connected to a computer or DVD player. If you want to switch the image source from projector to other sources, you can do as follows.
Here is an explanation of the buttons and corresponding sources.
The number 1 refers to HDMI and Video sources.
The number 2 refers to VGA port sources.
The number 3 refers to USB port sources (computer display or external devices).
The number 4 refers to Network and Screen Mirroring sources.