The Atlona AT-VGA11S is the VGA Ground Loop Isolator, designed to reduce video noise in VGA (RGBHV) signal. Noise may often occur from the ground loop, difference of the resistance in the electrical system. The VGA11S is a VGA in and VGA out box which is capable of supporting any HD15 type format(RGB, RGB+HV, RGBS, etc…) and capable of resolutions up to 2K (2048x1536).
When you connect your computer to a projector or a TV, a path is provided for electricity to flow from one wall socket to another as the electrical system tries to balance itself. This causes your video display to show lines and have shaking images.