I am not able to resolve this simple issue.
I am trying to connect my device to Eclipse via USB cable.
On my PC, I have installed Eclipse and the Android SDK and
I know this is a little old, but I was having the same issue. I tried all the options of setting usb debugging (off), disconnecting, restarting phone, usb debugging (on), connecting the phone and it just wouldn't connect.
I ended up installing the latest version of Kies on my machine and added the Unified option at the end of the installer and I then the phone would connect. (Not sure i needed the unified option) but it worked for me.