Although HDMI cables are gradually replacing the use of RGB cables, some older model computers are still equipped with RGB ports. RGB stands for "Red, Green, Blue," which are the main colors used in signal separation to create all video signals. By connecting two computers using an RGB cable and the 15-pin VGA ports located on the back of each computer, you can send video signals to the second computer monitor.
Shut down both computers, and make sure the power is off before you attempt to make the connection.
Determine which computer will be the output, and designate the other computer as the input. The output computer will transmit video and audio signals to the input computer.
Attach one end of the RGB cable plug into the 15-pin VGA output jack on the output computer and the other end of the RGB cable plug into the 15-pin VGA input jack on the input computer. Secure the cables on either end by fastening the two screws on both sides of the plug.