The radio transmitter is what determines the opening and closing of automatic garage doors. That means automatic garage door openers rely on the transmitters to work. Besides that, the doors come with a remote which transmits signals to the receiver. If the receiver recognises the signals sent, it opens the door. This convenience offered by automatic garage doors is the reason many homes have invested in them today.
However, your door will jam or become inefficient if you use it inappropriately or fail to maintain it properly.