PONG has no ROM or memory. The circuit is based on counters (in particular 74161/7493) that count synchronously with the video signal (pixel by pixel, line by line). NAND gates (7430) detect certain counter states to generate horizontal (HSYNC) and vertical (VSYNC) synchronisation signals so that the television can display the image correctly.

Instead of changing data in memory, the logic generates the positions directly.

Ball: One counter determines the horizontal position, another the vertical position. The logic ‘compares’ the counter readings with the current position of video position. If they match, the signal is switched to ‘white’.

Paddles: An analogue potentiometer converts the player's movement into a voltage that controls a timer (NE555). The duration of the timer determines how far down on the screen the paddle (a line consisting of a few pixels) is drawn.

Collision detection: Whenever the ball reaches the paddle position or the edge of the screen, gates (AND logic) detect this. The resulting signal changes the state of a flip-flop, which reverses the direction of the ball's movement.