This is my understanding of how it works (very basic)
1. A person enters your code into the gate controller keyboard.
2. The gate controller calls your cell phone.
3. You answer the call creating a link between your cell phone and the gate controller.
4. You enter the gate open code #9 on your phone.
5. The gate controller hears that code and opens the gate.

When the gate controller calls you and you answer, you now have a direct path into the gate controller.

Patrick T. Caezza
Santa Paula, CA 93060
C-7 - Low Voltage System Contractor - Lic# 992448