A little bit of a disclaimer, I have very little knowledge of the correct terminology for some of the things I'm going to ask about, and I apologize in advance

I have a Nexus S 4g phone that is, at the moment of writing, connected to my 11.10 computer through its USB charger cable. In the past, connecting the phone like this has allowed me to transfer files between my computer and my phone; I'm able to get my music onto my phone, and my photos onto my computer, for example. For some reason, this has stopped working. My phone still charges its battery when connected to the computer, but neither the computer nor the phone recognized that they are connected.

Is there something I can do to get the phone and the computer to detect each other? I don't know how to fix this, and it's more than a little frustrating. Any help would be greatly appreciated.