RE: Walkera Dragonfly 22E Sim Cable Help
To assign an IRQ to your printer port, go to Control Panel, double click "System", click the "Hardware" tab, then click "Device Manager". Find the "Ports (COM and LPT)" entry and expand it (click on the +). Right click your printer port and choose "Properties". Click the "Port Settings" tab and make sure "Use any interrupt assigned to the port" is checked. You will have to reboot if you make a change.
Hope this helps!
-JT