A clear plastic box with a receiver for garage door control messages

This receiver is matched to the Keyboard Remote transmitter, because only these use the same unique preamble code (Not DUMPF!).
Two secret codes are included in the program, which are not the numbers shown here.
The first causes a closure to ground of the output for 0.6 second. This wire is directly in parallel with both the Door Controller, which uses a keypad fastened to the outside wall, and to a manual push-button inside the garage.
The second cancels a 15-second hold caused by receiving any code other than these two. During this hold only this second code is acted on. Additional incorrect codes received extend the hold.
The receiver is powered from the door operating motor, same as the "Genie" receiver it replaces. Since this voltage exceeds the maximum rating of the 78L05 regulator, it is reduced with a zener diode and a resistor in series. These are mounted outside the receiver. There is a reservoir capacitor inside the receiver because the supply is unsmoothed.
The pin selection for the DA9S connector supports both service and programming modes. However, to program the receiver a supply voltage is needed. There are test points for this, as shown in the circuit diagram.
This shows the circuit board exposed by removing it from the clear plastic box:

Here is the circuit diagram. It does not show a voltage-dropping series 30-ohm, 2W resistor amd 10-Volt, 1W zener diode in the supply line.

Here is the program code.