I bet many of you guys weren't even born back in 1972. Neither was me.
In August 1972, the Magnavox Odyssey was launched in the NA. It was the first commercial home video game console to be released, designed by Ralph H. Baer and assisted by the engineers Willian Harrison and Willian Rusch. They began around 1966 and had a prototype known as Brown Box finished by 1968, but it was never released.
So... How does this used to work?
The Odyssey could be powered by six C Batteries, which were included. But you could also use an A/C power supply, sold separately. Unfortunately, the console lacks sound compatibility. Ralph Baer proposed a sound extension, but it was rejected.
There was no color, only black and white. Usually, the player was represented by a white square on a black screen. But, there was a way to make it more "colorful": The Odyssey was sold with translucent plastic overlays that you could put on your television screen to simulate backgrounds. Unfortunately, only two television sizes were supported.
A total of 27 games and 12 different cartridges were released. Most of these games used a similar gameplay, since the technology was very limited. You could use different overlays with the same games, only changing the rules to play. By the way, there was no score on-screen, so the Odyssey used poker chips and score sheets so you could keep your score in the real world.
This is Pong, using the overlay.
If you want to see the Odyssey in action, check out this video I found on Youtube. You can learn a lot more.
Yep, video-games sure evolved with time.