I have tried connecting an old USB Bluetooth dongle I used to use with my G4 iMac nearly 20 years ago to my Cube, but it doesn't recognise it, nothing shows up in System Profiler. It still works as my Macbook Pro can see it when connected. Is there any reason why a Bluetooth dongle wouldn't work with a Cube? I'm pretty sure the G4/700 iMac I used to have was also USB 1.1.