John, you will need a couple of things:
1) A slave usb interface
http://www.ikarus-modellbau.de/onlin...08251.38233896
2) An adapter cable for your Futaba 9C
http://www.ikarus-modellbau.de/onlin...ca088.63839801
You will need to plug in both the GC and the slave cable into your computer.