I was with an instrument student in a P210 preparing to depart IFR from Leesburg, Virginia. The remote radio frequency wasn't operating, so instead we set up the frequency for the Ground Control Outlet and clicked the microphone to activate the autodial telephone patch to Dulles Approach for our clearance.
This is a companion discussion topic for the original entry at https://www.avweb.com/features/shortfinal/short-final-458