The Atari 800 computer system was introduced in 1979, with expansion slots for software cartridges and ports for connecting up to four floppy drives for data storage. The 800 is also equipped with a video port for hooking up an external monitor. If you have a flat-panel monitor with a VGA connection, you can hook it up to the Atari 800 using a 15-pin VGA cable. Image quality might not be what you are accustomed to seeing on a flat-panel screen, but remember, you're hooking up a computer more than 30 years old.
Turn off power to the Atari and the monitor.
Connect one end of the cable to the monitor port on the right edge of the Atari. The plug must be turned to line up with the metal pins in the Atari port.
Plug in the other end of the cable to the port on the rear of the flat-screen monitor.
Turn on the power to both components.
Press the menu and navigational buttons on your monitor to highlight "Screen Resolution" and adjust the image from the Atari to fit your monitor. The image will appear square, not rectangular or widescreen. This is normal for a computer of this age.