Gefen EXT-VGA-142N VGA video splitter

1 x VGA In, 2 x VGA Out, 1920 x 1200, Bandwidth 350 MHz The 1:2 VGA Hub allows computers with VGA graphic cards to display a picture on two VGA displays or projectors simultaneously, making it perfect for presentations where the operator uses a small monitor at the computer while the audience views the image on a second larger display or projector.
How It Works
The 1:2 VGA Hub is connected to a PC video source with a VGA (male to female) cable from the computers VGA graphics card port to the VGA Hub?s input connector.

There are two VGA outputs on the 1:2 VGA Hub. VGA output #1 is the Primary connection, which queries the Primary Display attached to it and determines the possible video resolutions, timings and frequencies that can be used to create a picture. This information is called EDID (Extended Display Identification Data) and it is used to create a picture on all attached displays.

VGA output #2 is connected to the second (Secondary) display and creates an image by following the EDID settings obtained from the first (Primary) display; therefore, both displays should be capable of the same resolutions and refresh rates in order to display an identical picture.