Garmin G900X Installation And Maintenance Manual page 570

8. Select the Serial Port on the PC that will be used to communicate with the GDC 74(X), and click
'OK'.
9. After communication with the GDC 74A is established, the 'Full Backup' screen appears while a
full backup of the original unit setting is saved to a file named
BKUP_(serial_num)_YYYYMMDD_ HHMMSS.txt. This file can be used (by Garmin) to
restore the unit to the original settings if necessary.
10. After the full backup file has been created, the 'Prepare To Take Measurements' screen appears
while the program retrieves the unit type from the GDC 74A.
11. After the unit type has been determined, the 'Set altitude to 0 ft' screen (Figure D-6) appears.
12. Per the on-screen instructions, set the pressure control system to a pressure altitude of 0 feet.
13. Allow the on-screen altitude reading to stabilize, then click 'OK'.
Page D-58
Revision D
Figure D-5. Serial Port Pull-down List
Figure D-6. 0 Feet Calibration Screen
G900X/G950 Installation and Maintenance Manual – Troubleshooting
190-00719-00