(Presuming what you really want is to be able to remotely close the garage door)

How about...
An X10 telephone responder to answer the phone and generate X10 commands...
A universal module (UM506) in parallel with your in-the-garage door control switch, in dry contact closure mode, to activate the switch...
But you don't want anyone with an X10 RF transmitter to be able to open your garage door. You need to enable the UM506 only when the garage door is open. Put a normally open switch in series with the UM506, which is closed only when the door is fully raised.

This will allow you to send a signal that will close but not open the garage door.