Many vehicles are equipped with a built-in HomeLink® universal transmitter.  This built in remote can learn the codes for up to three remote-controlled devices through a simple training process. The transmitter can then activate these devices at the push of a button ­ all from one unit permanently mounted in you vehicle's sun visor or overhead console. The HomeLink universal transmitter is compatible with gate operators, garage door openers, RF door locks and is even capable of arming and disarming security systems.