I use it to send a course to my device. When you click on this button, you should get a window asking you which device you want to send it to. If it's a USB device (such as an Edge), then you have to have it connected to your computer.
That's what I'd expect, but it doesn't work. I select an Activity and click it. As nearly as I can tell, it does nothing at all. Nothing shows up on the I have a GPSmap 60CSx. It is connected and recognized, since I can do normal uploads. I have it set to USB when I try.
Maybe the 60CSx doesn't support downloads from Connect?
Maybe the 60CSx doesn't support downloads from Connect?
Offhand, I don't know. I'm not that familiar with the handheld mapping units, but I suspect that they do not support working with courses, which is what happens when you send an activity to a fitness device. But I could be wrong about this.
One way that might work would be to export your activity as as tcx (one of the buttons to the left of the "send to device" button). Then import the tcx file into Base Camp, and then send it to your 60CSx from Base Camp. However, as I said, I'm not that familiar with the mapping units nor am I very familiar with Base Camp, so I'm not positive this would work.