I had some issues getting my computer to recognize my Polar device (CS400) the first few times. Of course, I refused to pay the rediculous price for the "official" Polar IrDA adapter and got some no-name one off eBay. Once I figured out which driver to install (I had a choice of 4) I put the settings on my Polar Trainer software to USB thinking "I'm using a USB adapter, that must be what I should set it to." But no, that didn't work, so I set it to IrDA and finally it worked. It was also very fussy about exactly where I placed my Polar computer in relation to the sensor. But as I learn the little intricacies, it seems to be going a lot smoother now.