Fixed Code (DIP Switch)

A fixed code DIP switch system is the security method used on garage door openers manufactured before the mid-1990s and still found on some low-cost units. DIP stands for dual in-line package, referring to the physical format of the small bank of toggle switches.

The system works by having a matching bank of small toggle switches (typically 8 to 12, depending on the manufacturer) in both the handheld remote transmitter and the motor unit receiver. Setting a pattern of ON and OFF positions on the switches encodes a binary number. The receiver only responds when it receives a signal matching the exact pattern. To pair a new remote, an installer opens the remote case and moves the switches to match the pattern set on the receiver.

The weakness of fixed code is that the transmitted code is the same every time the button is pressed. Anyone with a radio scanner near your driveway can capture that code and replay it to open your door, a technique called a replay attack. This vulnerability is why manufacturers developed rolling code (also called hopping code) technology in the mid-1990s.

Rolling code systems replaced fixed code on most residential openers. The fixed code DIP switch format survives in some commercial and industrial operators where rolling code compatibility is not required.

The logic board on a modern opener replaces the DIP switch entirely. Instead of physical toggles, the logic board stores a rolling code generated during pairing and changes it cryptographically after each use. The learn button initiates that pairing process on current openers.