Abstract: A door operating system for moving a door about a vertical pivot axis between a closed position and an open position. The door operating system includes a driver including a free-ended output shaft and linkage for operably connecting the output shaft of the driver with door. An adjustable and selectively operable coupling is disposed between the free-end of the output shaft of the driver and the linkage. The adjustable coupling has a pair of coaxially spaced and adjustable interfaces. A first adjustable interface is defined between the free-end of the output shaft and the coupling while a second adjustable interface is defined between the coupling and the linkage whereby allowing for a high resolution, angular adjustment of the position of the door.