Last week I was curious about the signaling used by my garage door opener to its wired remote.  My garage door opener has a wired remote panel with three functions:

  1. light on/off
  2. open/close door
  3. lock.

Below are scome oscilloscope shots with my comments of how the signalling works in case someone else out there is also interested.  The motor control units sends an inverted periodic pulse train. The multiple functions are controlled via modulating the pulse width.  


This data might be interesting if you wanted to add an RFID keypad, improved & more satisfying wired panel, or BLE keypad. Find me on Twitter @roteno if you build something & found this useful.   



IDLE STATE - normal state of the system while unlocked & not being operated by a user 

Garage Door Signaling - IDLE STATE

Period: 12mS Vmax: 24V pulse width: 190uS 


IDLE LOCK STATE - puts the system into a idle locked state that disables the wireless keypad open/close door functionality. Wired door open/close functionality continues to work. 

Garage Door Signaling - IDLE LOCK STATE

Period: 200mS Vmax: 24V pulse width: 100mS (idle state 12mS period & 190uS pulse width are pressent as well) 


LIGHT ON / OFF - toggles the internal light on & off

Garage Door Signaling - LIGHT ON / OFF COMMAND

Period: 12mS Vmax: 24V pulse width: 2.6mS 


LOCK ON / OFF - toggles the lock state on & off

Garage Door Signaling - LOCK COMMAND

Period: 99mS Vmax: 24V pulse width: 24mS 


DOOR OPEN / STOP / CLOSE - toggles system between open garage door, stop door movement, close door   


Short the two wires.  Pulse width > 200mS.